STU vs GT2 vs T3 vs EP pace at Buttonwillow Raceway Park
Quickest here:STU 1:50.913 Tony Rivera, Cal Club 2026 qualifying · GT2 1:42.698 Tim Carroll, Cal Club 2026 qualifying · T3 1:55.675 Scotty B White, Cal Club 2026 race · EP 1:53.088 Glen McCready, Cal Club 2025 qualifying
STUGT2T3EPsolid race · dashed qualifying · slower is lower
STUGT2T3EPsolid race · dashed qualifying · each class's best lap as a share of STU's at the same event (the reference class, changeable above); 100% is level, higher is quicker
Event
STU
GT2
T3
EP
Qual best
Race best
Trap
Qual best
Race best
Trap
vs STU
% of STU
Qual best
Race best
Trap
vs STU
% of STU
Qual best
Race best
Trap
vs STU
% of STU
Cal Club 2026 CALCL262026-02-21
1:50.913Tony Rivera · fastest of 6 · top 5 within 14.1s-4.488s (-3.89%)
1:52.737Tony Rivera · fastest of 7 · top 5 within 7.7s-0.903s (-0.79%)
135.2Tony Rivera+21.8 mph (+19.3%)
1:42.698Tim Carroll · fastest of 8 · top 5 within 7.4s-3.120s (-2.95%)
1:44.128Tim Carroll · fastest of 8 · top 5 within 4.3s-2.798s (-2.62%)
155.7Rocky Crocker+37.8 mph (+32.1%)
-8.609squal -8.215s
92.4%qual 92.6%
1:55.970Scotty B White · fastest of 4 · top 4 within 10.5s+0.005s (+0.00%)
1:55.675Scotty B White · fastest of 5 · top 5 within 12.1s-0.522s (-0.45%)
137.2Scotty B White+25.7 mph (+23.1%)
+2.938squal +5.057s
102.6%qual 104.6%
1:57.474Kurt Frietzsche · fastest of 4 · top 4 within 4.5s+4.386s (+3.88%)
1:57.999Kurt Frietzsche · fastest of 4 · top 4 within 4.9s+4.512s (+3.98%)
131.6Joe Carr+23.8 mph (+22.1%)
+5.262squal +6.561s
104.7%qual 105.9%
66 rule changes (STU: 17, GT2: 8, T3: 18, EP: 23)19 weight · 6 cars added · 6 induction · 6 tyres & wheels · 4 engine · 2 suspension & brakes · 1 aero · 22 wording · GT2 Porsche 911 SC gains option of 4.0L 4V engine at 2350 lbs or 4.0L 2V at 2275 lbs. · M3 E92 classified in GT2 with 3999cc V8, 35mm restrictor, 3300 lbs minimum weight. · T3 Ford Mustang V6 Spec Line expands to include 2005-2010 chassis and body with 2011-2014 engine. · T3 Nissan 350Z DE Motor loses 25 lbs to 3100, HR Motor loses 25 lbs to 3250. · T2-T4 adjustable toe links now allow performance alternative bushings and spherical bearings, previously prohibited except in specified examples. · EP BMW 325i/is E30 throttle body specified as 60mm in fuel injection notes. · GT2 adds Cadillac CTS, Chevrolet Impala/Malibu/Monte Carlo/SS, Dodge Intrepid, Ford Fusion/Taurus, Lincoln MKS, Pontiac G8/GTO/Grand Prix, Toyota Camry, and Gen late Model Stock Car bodies. · GT2 Mazda BP engine 1839cc classified with 46mm turbo inlet restrictor, 2250 lbs minimum weight. · 991.2 GT3 Cup throttle body restrictor increases from 65mm to 70mm; 997.2 loses 100 lbs to 2800; Corvette LS engines get larger restrictors across multiple displacements and model years; LS3 and LT1 weight reduced 100 lbs each to 3150. · STU Mazda MZR (LF, L3, L5) Turbo classified; Jack Spania Racing 70 mm intake manifold and Fab9 Tuning bottom-mount turbo kit approved. · T3 Ford Spec Mustang restrictor opens to 45mm, weight drops to 3400 lbs. · T3 BMW Spec E9X tire width increases to 255 from 225; spec E9X tire or any DOT permitted. · T3 SpecE46 permitted tire width increases from 225 to 245. · T2, T3, T4 cars may relocate under-dash electronics and fuse boxes for access after roll cage installation. · T4 Performance now permits 1-piece alternative rotors matching spec line sizes; alternate brake kits allowed same. · EP Triumph TR2-TR4A allows 5-speed gearbox without overdrive; removes Weber carb and weight specification. · EP BMW Z3 2.5L restrictor reduced 52mm to 50mm, weight increased to 2550 lbs base; five other BMW models get smaller restrictors. · STU 36mm restrictor allows 2830 lbs (up 10 lbs from 2820); 37mm allows 2980 lbs (down 5 lbs from 2985). · STU cars over 3150 lbs lose 275-tire option with 2% weight adder. · STU Honda K20 and K24 engines lose 2% minimum weight penalty. · T3 Ford Mustang EcoBoost loses optional 2-piece 355mm Brembo rotor brake kit option with 50 lb penalty. · EP Nissan 280Z minimum weight reduced from 2560 to 2400 lbs. · EP Mazda MX-5 1.8L 90-97 weight reduced to 2125 lbs from 2150 lbs. · HP Austin-Healey Sprite/Midget 1098cc minimum weight drops 80 lbs to 1550. · HP Volvo 142/142E gains compression ratio limit 12.0:1 and valve lift limit .425". · HP Mini Cooper 07-15 valve lift reduced to .390", from .450". · FP and HP Volkswagen Rabbit descriptions updated: Convertible changed to Cabriolet in FP; Cabriolet added to three HP engine variants. · EP, FP, HP: rear drum brake to disc conversion clarified; rotors solid, diameter limited to largest front rotor permitted. · EP Ford Mustang (94-98) fuel injected throttle body inside diameter specified at 60. · STU Honda K24 engine swap weight increases by 2% effective November 1, 2025. · T3 Honda S2000 wheels grow to 17x9.0 front and 17x10 rear; tyres widen to 255 front and 275 rear. · T3 and T4 Mazda MX-5 Miata models add approved gear kit PT#-0000-02-6100 to notes. · T4 Mazda MX-5 Miata/Club/RF (19-24) and (16-18) remove discontinued hardtop part #0000-07-5901; T3 MX-5 Miata (16-18) and Global Cup ND (16-21) same. · HP Plymouth Arrow transmission max speeds clarified to 4 or 5. · EP, FP, HP wheel diameter added to Appendix G as absolute maximum specification. · EP, FP, HP throttle body inside dimensions must remain stock with +/-.25mm tolerance; butterfly dimensions stock in FP, HP only. · STU Lotus Elise SC and Exige SC weight reduced from 2450 to 2250 lbs. · GT2 Porsche 911 Coupe & Targa may use 993 3.8 RSR rear deck lid or approved aftermarket reproductions. · STU-TCR tire width increases to 275 with weight adder raised from 100 to 150 pounds. · STL/STU Lotus weight reduced: Evora GT4 to 2700 lbs, Elise Cup R to 2250 lbs, Elise/Exige SC to 2450-2550 lbs. · T2, T3, T4 Spec Lines table header changed from T2 to ET. · EP BMW Z4 03-05 restricted to 52mm flat plate intake restrictor. · EP Fiat 124 Spider 1600 & 2000 weight drops 50 lbs to 2000; carburetors gain 2mm chokes to 36mm. · STU 2.8-3.2L N/A engines now allow 245 max tire width; over 3150 lbs may run 275 with 2% weight penalty. · STU Mazda MZR may use Goodwin 61-2510 or Gato Performance 31972 intake manifold. · STU Honda JDM H23a added, 2259cc displacement, minimum weight per Chart, must meet ST engine regulations. · BMW Spec E46 in T3 updates to SpecE46 rules Version 3.0. · HP Fiat X-1/9 base weights reduced 50–53 lbs across 1300 and 1500 spec lines. · STU wheel width rules clarified: cars ≤2,850 lbs max 8 inches, cars >2,850 lbs max 9 inches. · STU Spec Line GT3U minimum weight reduced from plus 250 to plus 225 pounds; wheel and tire options clarified with weight adjustments. · T3 Ford Mustang V6 15-17 weight drops 50 lbs to 3350, brake options clarified with M2300V now 50 lb penalty or Brembo alternative. · T3 BMW Spec E46 rules updated to Version 3.0 from Version 1.1. · Chevrolet Spark 16-22 classified HP Pre at 1850 lbs minimum weight, fuel injected, 1399 cc. · HP Ford Festiva 88-93 minimum weight drops to 1600 lbs, variants to 1640 and 1680 lbs; compression ratio raised to 11.0:1. · T3 BMW Spec E46 updates to SpecE46 rules Version 1.1 dated Jan. 6, 2025. · T3 Ford Mustang V6 11-14 minimum weight drops 25 lbs to 3325. · EP BMW Z3 and 3-series models get smaller intake restrictors: Z3 2.5L to 52mm, Z3 2.8L to 55mm, 328i to 58mm, 325i to 56mm. · EP, FP, HP: interior or exterior mirrors meeting rule 9.3.36 now permitted. · EP Honda S2000 1997cc base loses 75 lbs to 2375; 2157cc base loses 60 lbs to 2450. · EP Mazda MX-5/Miata 99-05 minimum weight drops to 2100 lbs, 2153 lbs with power adder, 2205 lbs with two adders. · GT2 Pontiac Fiero changes from FWD to RWD; hood bulge permitted for front engine relocation. · TA2 and STO OEM wings no longer exempt from rear wing height rule at roof peak. · STU BMW N54/N55 3.0L classified at Chart +3% minimum weight; N54 twin turbo not allowed. · STU Mini Cooper S SC supercharger pulley diameter reduced from 2.285 to 2.185. · STU Honda K20C1 Turbo I4 exempted from 3% DI weight adder in Spec Lines Table A. · STU GT3U minimum weight increases 150 to 250 pounds.showhide
GT2 Allow Larger Air Cooled Engines in Porsche 911 GT2 #39249enginefasterGT2 Porsche 911 SC gains option of 4.0L 4V engine at 2350 lbs or 4.0L 2V at 2275 lbs.
GT2 Classify T1 BMW in GT2 #39408cars addedneutralM3 E92 classified in GT2 with 3999cc V8, 35mm restrictor, 3300 lbs minimum weight.
T3 Please change 2011-2014 Mustang V6 Spec Line to 2005-2014 #39558wordingneutralT3 Ford Mustang V6 Spec Line expands to include 2005-2010 chassis and body with 2011-2014 engine.
T3 Nissan 350Z Weight Request #39598weight -25 lbsfasterT3 Nissan 350Z DE Motor loses 25 lbs to 3100, HR Motor loses 25 lbs to 3250.
T3 Allow Alt Bushing Material in Toe Links #39607suspension & brakesfasterT2-T4 adjustable toe links now allow performance alternative bushings and spherical bearings, previously prohibited except in specified examples.
EP Request to Update E30 BMW Throttle Body Diameter Verbiage #39363wordingneutralEP BMW 325i/is E30 throttle body specified as 60mm in fuel injection notes.
GT2 Additional Body Options to Replace Older Stock Car Bodies #39086cars addedneutralGT2 adds Cadillac CTS, Chevrolet Impala/Malibu/Monte Carlo/SS, Dodge Intrepid, Ford Fusion/Taurus, Lincoln MKS, Pontiac G8/GTO/Grand Prix, Toyota Camry, and Gen late Model Stock Car bodies.
GT2 GT3 Turbo to GT2? #39365cars addedneutralGT2 Mazda BP engine 1839cc classified with 46mm turbo inlet restrictor, 2250 lbs minimum weight.
GT2 Tech Bulletins for GT2 and GT2-ST #39537induction -100 lbsslower991.2 GT3 Cup throttle body restrictor increases from 65mm to 70mm; 997.2 loses 100 lbs to 2800; Corvette LS engines get larger restrictors across multiple displacements and model years; LS3 and LT1 weight reduced 100 lbs each to 3150.
STU Request for Permission on Aftermarket Turbo Kit and Intake #39529cars addedfasterSTU Mazda MZR (LF, L3, L5) Turbo classified; Jack Spania Racing 70 mm intake manifold and Fab9 Tuning bottom-mount turbo kit approved.
T3 Request to Allow Spec Mustang to Touring 3 in Appendix M Trim #39196weight -50 lbsfasterT3 Ford Spec Mustang restrictor opens to 45mm, weight drops to 3400 lbs.
T3 Tire Help for Spec E9X in T3 #39222tyres & wheelsfasterT3 BMW Spec E9X tire width increases to 255 from 225; spec E9X tire or any DOT permitted.
T3 SpecE46 Tire Sizing #39292tyres & wheelsfasterT3 SpecE46 permitted tire width increases from 225 to 245.
T3 Alternate Placement of Fuse Panel and Electronics Request #39370wordingneutralT2, T3, T4 cars may relocate under-dash electronics and fuse boxes for access after roll cage installation.
T3 Clarify T4 Brake Rotor Allowance #39503suspension & brakesneutralT4 Performance now permits 1-piece alternative rotors matching spec line sizes; alternate brake kits allowed same.
EP TR2 Notes E&O #39180wordingunclearEP Triumph TR2-TR4A allows 5-speed gearbox without overdrive; removes Weber carb and weight specification.
EP Balance of Power #39187induction +50 lbsslowerEP BMW Z3 2.5L restrictor reduced 52mm to 50mm, weight increased to 2550 lbs base; five other BMW models get smaller restrictors.
STU Turbo Inlet Restrictor Table #38961inductionslowerSTU 36mm restrictor allows 2830 lbs (up 10 lbs from 2820); 37mm allows 2980 lbs (down 5 lbs from 2985).
STU 275 Tire Rule #38983tyres & wheelsslowerSTU cars over 3150 lbs lose 275-tire option with 2% weight adder.
STU STU Honda Engine weight penalty #39375weightfasterSTU Honda K20 and K24 engines lose 2% minimum weight penalty.
T3 T3 Ecoboost Mustang clarification #39236wordingunclearT3 Ford Mustang EcoBoost loses optional 2-piece 355mm Brembo rotor brake kit option with 50 lb penalty.
EP Please Lower Weight of 280Z #38871weight -160 lbsfasterEP Nissan 280Z minimum weight reduced from 2560 to 2400 lbs.
EP Miata Weight Adjustment Follow Up #38949weight -25 lbsfasterEP Mazda MX-5 1.8L 90-97 weight reduced to 2125 lbs from 2150 lbs.
EP Weight Break for 1098 Midget / Sprite #38970weight -80 lbsfasterHP Austin-Healey Sprite/Midget 1098cc minimum weight drops 80 lbs to 1550.
EP HP Volvo 142 spec omission #38994engineslowerHP Volvo 142/142E gains compression ratio limit 12.0:1 and valve lift limit .425".
EP HP Mini DOHC 1.6 #38996engineslowerHP Mini Cooper 07-15 valve lift reduced to .390", from .450".
EP Add to Rabbit description #39019wordingneutralFP and HP Volkswagen Rabbit descriptions updated: Convertible changed to Cabriolet in FP; Cabriolet added to three HP engine variants.
EP Clean-up 9.1.5.E.7e #39025wordingneutralEP, FP, HP: rear drum brake to disc conversion clarified; rotors solid, diameter limited to largest front rotor permitted.
EP Add TB size to Ford Mustang (94-98) Spec Line #39130wordingneutralEP Ford Mustang (94-98) fuel injected throttle body inside diameter specified at 60.
STU Non-Homologated Engine Swaps - Specifically K24A2 w/ Honda CRZ #38746weightslowerSTU Honda K24 engine swap weight increases by 2% effective November 1, 2025.
T3 Make the S2000 Competitive Again #38470tyres & wheelsfasterT3 Honda S2000 wheels grow to 17x9.0 front and 17x10 rear; tyres widen to 255 front and 275 rear.
T3 ND Gearset Request for T4 #39166wordingneutralT3 and T4 Mazda MX-5 Miata models add approved gear kit PT#-0000-02-6100 to notes.
T3 ND Spec Lines Wrong PT#'s #39170wordingneutralT4 Mazda MX-5 Miata/Club/RF (19-24) and (16-18) remove discontinued hardtop part #0000-07-5901; T3 MX-5 Miata (16-18) and Global Cup ND (16-21) same.
EP HP Plymouth Arrow spec omission #38995wordingneutralHP Plymouth Arrow transmission max speeds clarified to 4 or 5.
EP Add Wheel Diameter to Appendix G #39008wordingneutralEP, FP, HP wheel diameter added to Appendix G as absolute maximum specification.
EP Add TB ID tolerance to general Prod rules #39009wordingneutralEP, FP, HP throttle body inside dimensions must remain stock with +/-.25mm tolerance; butterfly dimensions stock in FP, HP only.
STU Lotus Weight Reduction E&O #38919weightfasterSTU Lotus Elise SC and Exige SC weight reduced from 2450 to 2250 lbs.
GT2 Rear Deck Lid for Older Air-Cooled Porsche #38506wordingneutralGT2 Porsche 911 Coupe & Targa may use 993 3.8 RSR rear deck lid or approved aftermarket reproductions.
STU STU-TCR Adjustments #38723tyres & wheelsslowerSTU-TCR tire width increases to 275 with weight adder raised from 100 to 150 pounds.
STU Lotus Weight Reduction #38772weight -50 lbsfasterSTL/STU Lotus weight reduced: Evora GT4 to 2700 lbs, Elise Cup R to 2250 lbs, Elise/Exige SC to 2450-2550 lbs.
T3 Incorrect Touring Heading #38451wordingneutralT2, T3, T4 Spec Lines table header changed from T2 to ET.
EP BMW Z4 update #38490inductionslowerEP BMW Z4 03-05 restricted to 52mm flat plate intake restrictor.
EP EP Fiat 124 Spider Competition Adjustment Request #38498weight -50 lbsfasterEP Fiat 124 Spider 1600 & 2000 weight drops 50 lbs to 2000; carburetors gain 2mm chokes to 36mm.
STU 2.8-3.2L N/A Engine Allowances #38007tyres & wheelsunclearSTU 2.8-3.2L N/A engines now allow 245 max tire width; over 3150 lbs may run 275 with 2% weight penalty.
STU 2006-2015 Mazda Miata Intake Manifold #38422wordingneutralSTU Mazda MZR may use Goodwin 61-2510 or Gato Performance 31972 intake manifold.
STU Requesting Approval of the JDM Honda h23a #38489cars addedneutralSTU Honda JDM H23a added, 2259cc displacement, minimum weight per Chart, must meet ST engine regulations.
T3 correct letter 37421 #38204wordingunclearBMW Spec E46 in T3 updates to SpecE46 rules Version 3.0.
EP Base Weight Adjustment for H-Production X1/9 Spec Lines #38255weight -50 lbsfasterHP Fiat X-1/9 base weights reduced 50–53 lbs across 1300 and 1500 spec lines.
STU Wheel Size Inconsistency #38018wordingneutralSTU wheel width rules clarified: cars ≤2,850 lbs max 8 inches, cars >2,850 lbs max 9 inches.
STU Table C: STU-GT3U Clarification #38268weightfasterSTU Spec Line GT3U minimum weight reduced from plus 250 to plus 225 pounds; wheel and tire options clarified with weight adjustments.
T3 S550 Mustang #38061weight -50 lbsfasterT3 Ford Mustang V6 15-17 weight drops 50 lbs to 3350, brake options clarified with M2300V now 50 lb penalty or Brembo alternative.
T3 correct letter 37421 #38204wordingunclearT3 BMW Spec E46 rules updated to Version 3.0 from Version 1.1.
EP Request for Classification of Chevrolet Spark #37755cars addedneutralChevrolet Spark 16-22 classified HP Pre at 1850 lbs minimum weight, fuel injected, 1399 cc.
EP Request to Lower Ford Festiva Minimum Weight to 1600 LBS #37939weight -100 lbsfasterHP Ford Festiva 88-93 minimum weight drops to 1600 lbs, variants to 1640 and 1680 lbs; compression ratio raised to 11.0:1.
T3 SpecE46 Tire Change #37421wordingunclearT3 BMW Spec E46 updates to SpecE46 rules Version 1.1 dated Jan. 6, 2025.
T3 S197 Mustang V6 in T3 #37594weight -25 lbsfasterT3 Ford Mustang V6 11-14 minimum weight drops 25 lbs to 3325.
EP Request Competition Adjustment to BMW Z3 2.5L #37120inductionslowerEP BMW Z3 and 3-series models get smaller intake restrictors: Z3 2.5L to 52mm, Z3 2.8L to 55mm, 328i to 58mm, 325i to 56mm.
EP Interpretation of Production Rules on Mirrors #37235wordingneutralEP, FP, HP: interior or exterior mirrors meeting rule 9.3.36 now permitted.
EP Weight Reduction for Honda S2000 #37466weightfasterEP Honda S2000 1997cc base loses 75 lbs to 2375; 2157cc base loses 60 lbs to 2450.
EP Mazda 1999 Miata 1.8L #37488weight -50 lbsfasterEP Mazda MX-5/Miata 99-05 minimum weight drops to 2100 lbs, 2153 lbs with power adder, 2205 lbs with two adders.
GT2 Hood Bulge allowed #37000wordingunclearGT2 Pontiac Fiero changes from FWD to RWD; hood bulge permitted for front engine relocation.
GT2 OEM Wing Adjustment #37590aeroslowerTA2 and STO OEM wings no longer exempt from rear wing height rule at roof peak.
STU BMW N54/N55 Engine Allowance Follow Up #37447engineneutralSTU BMW N54/N55 3.0L classified at Chart +3% minimum weight; N54 twin turbo not allowed.
STU STU Mini Cooper pulley size clarification re: letter #36980 #37717inductionfasterSTU Mini Cooper S SC supercharger pulley diameter reduced from 2.285 to 2.185.
STU Question About a Weight Modifier #37782weightfasterSTU Honda K20C1 Turbo I4 exempted from 3% DI weight adder in Spec Lines Table A.
STU Increase Minimum Weight #37919weight +100 lbsslowerSTU GT3U minimum weight increases 150 to 250 pounds.
Cal Club 2025 CALCL252025-02-22
1:55.401Wilson Powell · fastest of 4 · top 4 within 8.7s
1:53.640Rylan Hazelton · fastest of 5 · top 5 within 8.0s
113.3Rylan Hazelton
1:45.818Brad McAllister · fastest of 6 · top 5 within 14.6s
1:46.926Brad McAllister · fastest of 6 · top 5 within 13.3s
117.9Guy Laidig
-6.714squal -9.583s
94.1%qual 91.7%
1:55.965Roger Eagleton · fastest of 6 · top 5 within 5.4s
1:56.197Scotty B White · fastest of 6 · top 5 within 3.8s
111.5J. David Orem
+2.557squal +0.564s
102.3%qual 100.5%
1:53.088Glen McCready · fastest of 5 · top 5 within 10.6s
1:53.487Glen McCready · fastest of 5 · top 5 within 10.6s
107.8Joe Carr
-0.153squal -2.313s
99.9%qual 98.0%
481 earlier rule changes on record, in force before Cal Club 2025 (from 2019)99 cars added · 78 weight · 47 induction · 26 engine · 22 tyres & wheels · 18 suspension & brakes · 14 aero · 2 removed · 170 wording · 5 other · EP BMW Z3 2.5L requires 52mm flat plate intake restrictor; Z3 2.8L 55mm; 328i/is E36 58mm; 328i/ci E46 58mm; 325i/is E46 56mm; 325i/is E36 56mm; 325is M-Technic 56mm. · GT2 STO aftermarket ABS weight penalty reduced from 100 lbs to 50 lbs. · T3 Nissan 350Z HR Engine FPR restrictor increases from 47mm to 49mm. · Ford SCCA Club Spec Mustang classified T3 at 3350 lbs with driver; Mazda SCCA Club Spec MX-5 classified T4 at 2500 lbs with driver. · EP BMW 325i/is E30 (84-91) weight reduced 50–52 lbs across three spec lines to 2150, 2204, 2258. · GT2 Panoz Esperante GTS adds 2013-2016 Ford EcoBoost Twin Turbo V-6 3496cc engine, 2600 lbs. · TA2 rear wing height rule clarified: OEM aerodynamic devices exempt from peak-of-roof requirement. · GT2 Sunbeam Tiger gains Holly 650 cfm carburetor alternate options PN #80541-1 and #80541-2. · STU Audi 1.8T wagon deleted; Porsche 944 1800 weight to Chart, turbo inlet restrictor removed. · STU-GT3 reclassified as STU-GT3U effective January 1, 2026. · STU GT3 TCR gains 275-width tire option with 100 lb weight penalty, but not in A compound. · T2, T3, T4 remove nine, nine, and thirty-six expired spec lines respectively, effective 2025-01-01. · Ford Spec Mustang moves to T3 with 44mm bore restrictor, 275 max tire, 3450 lbs minimum weight. · T3 Ford Mustang V6 (11-14) and (15-17) now permit cold air intake. · EP Triumph GT6 switches to three Weber 40 DCOE carbs with 28mm chokes, weight rises 50 lbs to 1990. · STL/STU: 90-05 Mazda Miata alternate front wheel hubs moved from General to specific part approval. · STU BMW N54/N55 turbo inlet restrictors now required per GCR definition; turbo swapping prohibited. · T3 VW Golf R (12-13 and 15-18) 36mm TIR placement now allows OEM turbo inlet, removing 60mm distance limit from impeller. · T2 and T3 Mustang spec lines remove redundant driveshaft alternate/aluminum allowance wording. · T2, T3, T4 fuel cell installations may remove charcoal canisters, emissions valves, and sensors. · T2, T3, T4 brake component wording clarified: 2-piece rotors allowed in T2 within 5% OE diameter, T3 within 2% OEM diameter. · T2, T3, T4 fuel cell cars may remove charcoal canisters, emissions valves, and sensors. · T3 and T4 Mazda RX-8 and MX-5 permit transmission kit #0000-02-5700. · Porsche Spec Boxster moves to T4, minimum weight 2750 lbs, requires 3 Super Tour events before Runoffs eligibility. · T4 BMW 320i 14-15 Spec Line expires 12/31/24 removed; Turner Motorsports intercooler #024703TMS02 allowed. · Cadillac CTS 02-07 3.6L classified in T3. · T3 BMW 328i/330i (06-12) model name updated; BMW 320i (14-15) newly classified at 3050 lbs. · T3 Subaru WRX STI max model year extended to 21, max tire size increased to 275. · T3 Honda HPD Civic Si FE1 newly classified with 1498cc engine, 18x8 wheels, 245 tires, 2950 lbs minimum weight. · T3 Subaru WRX STI 03-07 drops 100 lbs to 3200; Legacy GT/Spec B 05-09 drops 150 lbs to 3200. · HP Sprite and Midget 1275cc and 1098cc Level 2 compression ratio raised to 12.0:1. · EP Mazda Miata front and rear track widths increased to 1516/1534 mm (59.7/60.4 in.) across all generations. · STU Mini Cooper S SC 1900 restricts to 2.565 diameter pulley; 2100 allows 2.285 diameter pulley. · HP Volkswagen Golf and Jetta 85-92 track correction: front 1537mm (60.5in), rear 1529mm (60.2in). · STU RWD turbo cars no longer required to reduce restrictor by 1 mm from table. · T3 Honda Civic Si (2017-2021) restrictor removed, weight to 2950 lbs, Runoffs eligibility requires 3 Super Tour events. · T3 Subaru STI (15-20) and WRX STI (03-07) permitted to use OEM spec block #IAG-ENG-S550 and head studs. · Audi TT Coupe 08-14 classified in T3 with 36mm TIR restrictor, 1984cc, 3200 lbs minimum weight. · T3 Mazda MX5 Miata/Club/RF (19-24) newly classified at 2550 lbs, 17x8.5 wheels, 245 tyres, 280 mm brakes. · GT2-ST allows aftermarket replacement differential housings if exact equivalents. · GT4 cars now permitted in GT2-ST with factory restrictor, must comply with 2012 STO rules, slicks allowed with 100-pound penalty. · Ford Mustang GT 5.0L and V6 now permit Track/Performance Package parts in T2 and T3. · T2-T4 Ford Mustangs: remove 25 lbs penalty for non-OEM driveshaft, clarify alternate driveshaft allowances. · T3 Nissan 350Z DE engine now permits cold air intake. · Audi S4 (2000-2002) moves to T3 with 3400 lbs minimum weight, 38mm turbo inlet restrictor required. · T3 BMW Z4 3.0si expands to include 3.0i Roadster and Coupe (07-08); hardtop permitted with positive fasteners. · Nissan 300ZX 84-89 classified to EP at 2550 lbs minimum, 2960cc 6-cyl SOHC, fuel injection, 12.0:1 compression limit, 0.500" valve lift limit. · Mazda RX-7 92-97 newly classified EP Prep Level 2 at 2200–2310 lbs with 13B 6-port rotary engine. · EP Mazda RX-8 (04-11) alternate spec line removed; one primary line remains. · T3 Mazda MX-5 Global Cup Miata ND1/ND2 tire size changes to 225 DOT specification. · GT2-ST Acura NSX minimum weight raised to 3000 lbs, restrictor increased to 45mm TIR. · GT2-ST Corvette 14-19 LS2 restrictor increases from 78mm to 80mm flat plate. · T3 and T4 Mazda RX-8 may remove or disable factory oil injection system. · T2, T3, T4 driveshafts may use alternative materials or one-piece units; non-OEM adds 25 lbs. · Audi S4 00-02 in T3 must compete in 3 Super Tour events before Runoffs eligibility. · HP removes four redundant VW spec lines: Rabbit Cabriolet 1780, Scirocco 1588, Scirocco 1780 8-valve, Scirocco 1588. · Chevrolet Corvette C8 (2020–) classified into GT2-ST with 6162cc displacement, 3300 lbs minimum weight, 71mm restrictor. · 2015 Mitjet ST added to GT2, must run per VTS specifications with complete FIA form CdM008. · STU Mini Cooper S SC: alternate LEAP OMICRON hood scoop LEP-OMICRON3 permitted. · STU BMW S54 B32 OEM now permits dry sump oiling system. · T3 Spec Z 350Z rear wheel width increases to 10 inches; HR Engine restrictors change from 42mm to 44mm. · Audi S4 2000-2002 classified in T3 at 3400 lbs with 38mm turbo inlet restrictor required. · T2-T4 Spec Lines remove wheelbase requirement, replace with Required Restrictor specification. · T2 and T3 Nissan 370Z brake rotors enlarged: front 320x28 to 355x32mm, rear 320x16 to 350x20mm vented. · T3 Ford Mustang V6 (11-14) restrictor requirement removed; (15-17) brake penalty reduced to +50 lbs from +100 lbs. · T3 Nissan 350Z and 370Z now allow brake booster vacuum regulator, must not be in-car adjustable. · T3 Ford Mustang 4.6L restrictor holes increased from 40 mm to 45 mm. · T3 Mazda RX-8 Spec Line retention appeal directed to letter #35584 for ruling. · Mazda RX-8 04-12 expiration date removed; no longer expires 12/31/24. · T3 Subaru WRX (02-05) spec line expiration deadline removed; class now permanent. · HP Honda Civic 1.5 (88-91) weight reduced to 2175 lbs base, 2229 lbs with power adder, 2284 lbs with two. · GT1, GT2, GT3, GTL, GTX rear spoiler maximum surface area limit of 295.0 square inches removed. · GT1/GT2/GT3/GTL/GTX Direct Injection now permitted if OE, using only OE pump, hoses, injectors. · GT2 Chevrolet Corvette 7011 OEM 7 liter weight reduced 150 lbs, to 3125 lbs. · GT2/3 Nissan, Mazda, Mitsubishi 4G93, QR25DE/DD, QE25DE/DD Direct Injection now permitted per 9.1.2.F.7.5.E. · STL and STU power steering rules clarified to permit electric-assisted and hydraulic-assisted steering systems. · T3 Golf R 15-18 max wheel width increases to 9 inches, max tire size to 255. · T2, T3, T4 battery replacement wording simplified; OEM weight tolerance requirement removed. · T3 Ford Mustang V6 (11-14) gains approved strut tower brace and sway bar kit options. · T3 Ford Mustang EcoBoost 2015- intake restrictor increases from 35mm to 36mm TIR. · T4 now permits C-Spec cars to compete alongside B-Spec cars. · T2-T4 spec lines for 46 cars expire 12/31/24; appeal required to continue. · EP BMW Z3 2.5L weight increases to 2500 lbs, 2563 lbs with turbo, 2625 lbs with supercharger. · EP Mazda MX-5 1.8L 1990-97 minimum weight drops to 2150 lbs; 1994-97 variants to 2000, 2050, 2100 lbs respectively. · EP Triumph GT6 dual 1.75" carbs weight drops to 1940 lbs; triple Weber 40 DCOE options consolidated. · EP Honda S2000 fuel injected throttle body inside diameter increases from 62mm to 64mm. · EP Triumph TR8 dry sump allowance moved from carburetor line to notes section. · EP Porsche 944/924S 2.5L and 2.7L weight minimums corrected: 2479cc to 2306/2363 lbs, 2681cc to 2358/2415 lbs. · GT2-ST Dodge Viper hybrid kit restrictor reduced from 50mm to 45mm flat plates. · T3 Pontiac Solstice GXP front brake rotor increases from 296 to 355 mm vented. · T3 Nissan 350Z DE motor loses 75 lbs to 3125; HR motor gains 47mm restrictors, up from 44mm. · T3 Nissan 370Z model years expanded to include NISMO Edition through 2022. · T3 2010 Mustang GT 4.6 now allows 2013-14 GT style front/rear fascia, hood, and associated assemblies. · T3 BMW SpecE46 minimum weight drops 50 lbs to 2850. · T3 Subaru STI (15-20) minimum weight increases 100 lbs to 3450; all three STI variants get larger turbo inlet restrictors. · EP Porsche 944/924S combines 2.5L and 2.7L variants with new weights: 2250–2415 lbs depending on engine and year. · EP Triumph GT6 minimum weight reduced to 1800 lbs. · GTL spec lines moved to contiguous position with GT2 and GT3; GTA category and spec lines renumbered and moved behind GTL. · T3 Porsche Cayman (09-12) and (13-16) gear and final drive ratios adjusted; 09-12 6-SPD final drive 3.88 to 3.875, PDK 3.909 to 3.250; 13-16 6-SPD final drive 3.89 unchanged, PDK 3.91 to 3.250. · T3 Volkswagen GTI 06-10 turbo inlet restrictor increases from 36mm to 37mm. · T3 Volkswagen Golf R permitted model years extended from 15-16 to 15-18. · T3 Volkswagen Golf R 15-16 now permits Verkline WAS-048 camber arms. · BMW Spec E9X classified in T3 at 2975 lbs, must conform to SpecE9X rules Version 2.10, tire max 225. · T3 VW Golf GTI and Golf R TIR location clarified to maximum 60mm from impeller. · GT2-ST Dodge Viper including Comp Coupe, ACR/ACR-X with VRL front fascia loses 100 lbs. · EP Triumph TR8 78-81 removes alternate front hub allowance note; stock hubs now required. · EP Triumph GT6 carburetors change from SU or Stromberg to 1.5" Auto-type. · EP Triumph GT6 brakes may now use TR-6 standard or alternate calipers and discs. · GT2 Mazda 20B 3 rotor loses 220 lbs, to 2280, consolidating two spec lines. · 2012-2013 Volkswagen Golf R added to T3 as new entry with 1984cc engine, 3080 lbs DSG/3050 STD, 36mm turbo inlet restrictor. · T3 Mazda RX-8 removes transmission/final drive pairing requirement; T4 removes same requirement, adds Mazdaspeed radiator and coil spring kit. · T3 BMW 320i (14-15) gains aftermarket intercooler permission; T4 loses it. · T3 Nissan 350Z and 370Z maximum tire width increases from 245 to 255. · T3 Pontiac Solstice GXP minimum ride height set to 3 inches. · FP and HP Sprite, Midget, and Spitfire 1500 intake valve size corrected to 36.6/(1.44). · GT2 BMW engines: 3.4L 6-cyl at 2575 lbs, 4.0L V8 at 2900 lbs, 4.5L V8 at 2950 lbs, 5.0L V8 at 3000 lbs; S54 with 97mm stroke permitted at 2800 lbs. · GT2 Corvette C7 restrictor increases from 73mm to 77mm flat plate, removing weight penalty. · Toyota GR Cup and GR86 Cup (2022-) newly classified in STU at 2700 lbs with 2387 cc engine. · T3 Camaro V6 1LE and LT-I4 Turbo 1LE max wheel diameter increases from 18 to 20 inches. · T3 removes Toyota 2022-up GR Cup and 2022-up GR86 Cup entirely from Spec Lines. · EP Porsche 914-6 2.0L intake valves increase to 2.0 mm, exhaust valves corrected to 38.0 mm. · T3 Ford Mustang V6 (15-17) weight drops to 3400 lbs, brake penalties reduced to +100 lbs and +50 lbs. · BMW SpecE46 in T3 loses 50 lbs, to 2900. · T3 adds 2022 Toyota GR Cup and GR86 Cup, both 2387cc, 2700 lbs, 245/620R18 slicks, 332x32F/280x32R brakes. · 2009-2012 Porsche Cayman S classified in GT2, 3.4L, RWD, no PDK transmission allowed. · Fields Cardinal V8 classified in GT1 with Ford V8 engine, 4.9L displacement, 2100 lbs minimum weight. · T3 BMW Spec E46 weight reduced 25 lbs, to 2925. · T3 BMW 323Ci/Is weight reduces to 2750 lbs from 3000 lbs. · T3 BMW SpecE46 must conform to SpecE46 rules Version 2.10, updated from 2.7. · EP BMW Z3 2.5L intake restrictor reduced from 58mm to 56mm flat plate. · GT2 Ginetta G56 GTA may now use Factory installed ProMap ECU Map. · STU Mazda BP5A classified at 1839 cc maximum displacement, 2023-04-01. · T3 06-10 VW GTI, Jetta GLI allowed to use ECS Tuning performance alternative intercooler. · STU minimum weight chart updated: 2450cc to 2595lbs, 2600cc to 2710lbs. · T3 Porsche Spec Boxster tire rule updates to current SPB rules or any 245 DOT tire. · T3 06-10 VW GTI and Jetta permitted to use OEM VW knuckles 3C0407253F and 3C0407254F. · T3 BMW 320I now permitted to use aftermarket intercooler. · GT2 Mazda 13B Street Port turbo changes from EFR 76/70 to BW7670 or Garrett G30-660 with 46mm TIR at 2280 lbs. · Porsche Cayman (13-16) classified in T3 at 3225 lbs with 2700cc engine, 18x9 wheels, 245 tires. · T2/T3 Mustang GT 5.0L and V6 (11-14) may remove upper grille fog lights, replace with mesh or screen. · Hyundai Veloster Turbo 2018-2021 classified in T3 at 3050 lbs with 1584cc engine, 245 max tire size, specific suspension and brake modifications allowed. · T3 Volkswagen GTI and Jetta GLI now permit Verkline WAS-048 adjustable rear camber arms. · EP 79-85 RX-7 12A/13B brake spec simplification removes hub/rotor weight minimum allowance. · EP 280Z carburetor option adds Hitachi-SU 1bbl 46mm throttle bores alongside fuel injection. · EP Mazda RX-2, RX-3, RX-4, and 12A RX-7 now allow 2 bbl fuel injected throttle body w/ 42mm chokes on dual-y manifold. · EP Mazda RX-2, RX-3, RX-3SP, and RX-4 minimum weights reduced 50–52 lbs across all spec lines. · EP Triumph TR8 78-81 now allowed to run dry sump. · EP, FP, HP cylinder head ports limited to 1 inch maximum depth matching from mating surface. · EP Prep 280ZX (79-83) added to spec lines with 2425–2546 lbs, 2760cc SOHC 6-cyl, fuel injection, 12.0:1 compression limit, .500" valve lift limit. · GT2 Porsche SOHC 2478/2681/2992 turbo sizes increase from 42mm to 44mm SIR to TIR. · GT2-ST Chevrolet Corvette 14-19 L76 5967 restrictor increases from 70 to 73 mm. · GT2 Toyota 4A-F and 4A-FE 1.6L DOHC 16V engines newly classified in spec line. · GT2 Mazda 13B Street/Bridge Port turbocharger changes from EFR 70/76 to 76/70, compressor from 42mm to 46mm. · GT2-ST BMW E36/46 spec line adds MA Shaw carbon/composite door offerings to Notes. · GT3 normally aspirated cars may use intake chokes instead of SIRs, fitted to each carburetor barrel, same size as required SIR. · GT3 2.0L 4-valve non-turbo engines may run unrestricted at 2060 lbs instead of with a choke restriction. · GT2 Porsche 991.1 TBR 70–72mm, 991.2 weight 3100–3000lbs TBR 65–67mm, ABS penalties removed; GT2-ST Corvette LS engines flat plate 75–78mm, LS7 65–68mm; Viper weights 3275–3125lbs. · T3 Nissan 350Z and 370Z remove SPC Control Arms 72130, 72125, 72123; permit performance alternative front upper control arms. · T3 Nissan 350Z loses up to 75 lbs and gets 44mm restrictors; 370Z loses 100 lbs. Wheels widened front and rear. · T3 Ford Mustang EcoBoost 2015- turbo inlet restrictor increases from 34mm to 35mm TIR. · T5 class added as regional-only; T5 tyres maximum width 225, minimum aspect ratio 45. · T2-T5 Touring front and rear suspension maximum negative camber changed to 3.5 degrees. · GT2 TA2 and GTA throttle body part numbers updated to GM 90mm electronic #12570790 or Edelbrock 90mm mechanical #33869 or #3870. · GT2 Ginetta G56 GTA gains optional 18" x 9" and 18" x 10" wheels. · T3 Solstice GXP intercooler options expanded: Hahn HIC-1150 or Dejon FIC-SSA replaced with Performance alternative. · GT2/ST BMW E36/E46 now allows MAShaw body kit parts: wide body, bumpers, fenders, rockers, flairs. · GT2 Chevrolet Corvette L76 5967 restrictor increases from 73mm to 74mm. · T3 Subaru BRZ 2022- minimum weight up to 2975 lbs; spring rate to 1000 F/R, brake parts allowed without penalty. · VW New Beetle 2.5L 5-cyl added to EP at 2400–2520 lbs, 2480 cc, fuel injection, comp ratio 12.0:1 max, valve lift 0.500" max. · EP Mazda RX-7 12A/13B gains fuel injection option on dual-y manifold with 42mm choke(s). · EP VW Corrado 92-95 stroke corrected to 90.3 mm, displacement to 2792 cc. · GT taillights may now be original style or a panel graphic with functioning red LED brake lamps; wording change only. · Ginetta GTA G56 added to GT2 as spec car: 2600 lbs, 3.7L Ford V6 sealed, 6-speed Quaife sequential. · T3 Honda S2000 hardtop clarified: OEM, Mugen P/N 0000-04-2312, or aftermarket permitted if OEM roof silhouette retained. · T3 Pontiac Solstice GXP Coupe/Convertible 07-09 tire runout increases from 35mm to 36mm TIR. · GT2 BMW E36/E46 carbon roof and door suppliers added to notes: Lang Racing, 2M Automotive, Flossmann, MA Shaw. · GT2-ST BMW E46 M3, E36, Z3, 5000cc V8 can use 95mm S54 crankshaft at +150 lbs. · Audi R8 GT4 classified to GT2 with 5.2L displacement, 3000 lbs minimum weight, per factory specs restrictor. · STU Mazda 13B Turbo classified, streetport only, stock turbos prohibited, alternatives allowed. · STU OEM louver vents now exempt from vent count and 200 square inch allowance. · STU 2400cc non-4-valve engines gain 9% base weight reduction; DI turbo prep limits removed. · STU normally-aspirated 2976–3200 cc single-throttle engines lose 10% base engine weight reduction. · ST redundant language removed from balance shaft and pulley modification rules. · BMW 320i (14-15) classified in T3 at 3050 lbs with 18-inch wheels, 255/275 tires, 3.08 final drive. · T3 Subaru BRZ (2022-) and Toyota GR86 (2022-) permit 25mm front and 22mm rear sway bars, OEM trunk spoiler. · EP Subaru BRZ and Toyota 86/Scion FR-S model year ranges updated to 13-20. · EP Mazda MX-5 Global Cup 16-22 minimum weight set to 2400 lbs; sequential gearbox allowed with +150 lbs penalty. · BMW 128i (08-13) classified in EP at 2700 lbs minimum with stock throttle body, 11.0:1 compression ratio, 0.400 in. valve lift limits. · EP/FP/HP open cars may now use carbon fiber hardtops if they retain OEM appearance in all exterior profiles. · GT2 shock absorber attachment points clarified as moveable; wording correction only. · GT2 Porsche 104.0 x 88.0 engine weight increases from 1950 to 2090 lbs; 2V variants may use Borg Warner EFR 76/70 42mm turbo. · STU cars that qualified for 9 inch wheels in 2021 may continue through 2022 only. · STU splitter definition clarified: must be single-plane with no vertical deviations, attached to lowest front point. · T3 Honda Civic Si (2017-) spec clarified: wheels to 10" wide allowed with 50 lb. penalty, 1-piece rotor required. · Porsche Boxster Base 2005-2008 newly classified in T3 at 3000 lbs minimum weight. · T2-T4 Touring cars with alternative springs may use performance top hats with spherical bearings on shocks and struts. · T3 Subaru BRZ and Toyota 86 (2022-) wheel size corrected to 18 x 8 in., gear ratios and final drive specified. · EP Mazda RX-8 13B carburetor rules clarified: dual 2bbl carb, fuel injected throttle body, or stock fuel injection permitted. · EP and FP Production clarifies idle control valve rules: stock devices allowed original, removed with blocked ports, or mechanical replaced with electronic stock type. · STU BMW S52B32 minimum weight drops 90 lbs to 3110; max displacement cut to 3152 cc. · STU BMW S50B32 Euro classified at 3201 cc displacement, 3300 lbs minimum weight. · ST engine swap origin country requirement changes from North America to the United States for case-by-case approval. · STU Honda CRX (84-91) and Civic Del Sol (93-97) ineligible for front wheel drive weight reductions. · STU vehicles at or over 2950 lbs base weight may use 9 inch wide wheels instead of 8.0 inch maximum. · STU minimum weights reduced: 2450cc to 2596 lbs, 2500cc to 2635 lbs, 2550cc to 2675 lbs. · T2-T4 cars model year 2018+ may use non-OEM ECU with 75 lb weight penalty via spec line adjustment. · T3 Ford Mustang V6 (11-14) minimum weight reduced to 3350 lbs. · T3 Subaru STI 15-20 now allows SPC lower control arm 67660. · EP BMW Z3 2.5L intake restrictor reduced from 59mm to 58mm flat plate. · Ford Mustang 99-03 classified to EP at 2700/2768/2835 lbs; 94-98 Mustang weight reduced to 2550/2614/2678 lbs. · EP, FP, HP Improved Touring cars may use any DOT-approved tire per section 9.3.45 in Production class. · Ginetta G40 classified in GT2 with Mazda MZR/L5-VE engine, 2488cc or 2399cc, 1950 lbs base weight. · Toyota Supra GT4 added to GT2-ST: 3000cc, 3000 lbs minimum, factory restrictor. · GT2 Porsche 944/924 may use ERC 76/70 Turbo instead of Jayco super 50. · STU normally aspirated engines: minimum weights reduced up to 310 lbs; single throttle body weight reduction removed. · STU Audi A4 1.8T minimum weight fixed at 3050 lbs, VF30 turbo with 35mm restrictor now required only. · STL and STU Improved Touring vehicles must conform to 9.1.4 Tires & Wheels requirements. · T3 BMW 330i/Ci 01-06 loses 60 lbs to 3125 and runs 245 tyres instead of 275. · T3 Nissan 370Z 09-16 and 370Z NISMO 09-13 weight increased to 3375 lbs. · T3 FWD models standardized to 36mm turbo inlet restrictor; Focus ST brakes enlarged, final drive changed to 4.06 (1-4) 2.95 (5-6); GTI 14.5-17 gear ratios revised DSG/STD. · T2-T4 grill openings may remove non-metallic webbed false sections; 16 square inch limit removed. · T3 Spec Lines Subaru BRZ TS (13-21) added to class specification wording. · T3 VW GTI/Jetta GLI allows any 4-piston brake kit instead of StopTech only, max 355mm x 32mm. · EP, FP, HP classes allow stock/original idle control devices unmodified or completely removed with openings blocked. · EP Porsche 968 (92-95) now allows dry sump. · EP 1979-1985 Mazda RX-7 12A and 13B weight reduced by 50-53 lbs across all configurations. · GT2 Porsche Cayman 05-15 turbo restrictor increases from 70mm to 75mm. · STU engines may delete balance shafts and plug openings; alternate pulleys allowed for timing belt or chain operation only. · STU hood vents allowed to include louvers within 200 sq. inch area. · EP Porsche 968 intake valve size increased from 37 to 39.0 mm. · EP, FP, HP front-wheel-drive cars may alter body and suspension to install alternate transmission, transaxle, and axle shaft. · EP BMW Z3 2.5L allows alternate throttle body from 92-95 325i with Turner adapter; head casting 1738400 permitted with specific blocks. · GT2 Porsche Cayman 05-15 uses Throttle Body Restrictor instead of Flat Plate Restrictor at 2700 lbs. · STU adds Honda K23 with 2354cc displacement and minimum weight per chart, K24 block allowed with K23 internals and head. · STU Honda K23 internals rule relaxed to require only K23 crankshaft, allowing other internal modifications. · STL and STU piston engines clarified: intake manifold and cylinder head porting remains free. · T3 Scion FR-S/Toyota 86 GT and Subaru BRZ lose 75 lbs, to 2675 lbs minimum weight. · 2022+ Subaru BRZ and Toyota 86 newly classified in T3 at 2750 lbs with 245 max tires. · T2-T4 clarified: grill opening area may increase max 16 sq in for radiator cooling only, retaining factory mesh shape. · T3 BMW 335i eligible model years narrowed from 08-13 to 07-10. · T3 BMW 135i model years restricted from 08-13 to 08-10. · T2, T3, T4 radiator and coolant hoses may be replaced with aftermarket options; coolant temp sensor modification permitted. · T3 Nissan Z 350Z and 370Z suspension control arm options expanded from 'and' to 'or' for SPC parts. · T2, T3, T4 clarify that spec lines listing permitted or allowed parts are alternatives to category rules, not replacements. · EP Porsche 944S2 89-91 requires 56mm flat plate intake restrictor; comp ratio max 12.0:1, valve lift max 0.500". · HP Corolla GTS RWD (84-87) added at 2300 lbs; HP Corolla FX16 FWD (87-88) added at 2260 lbs; old Corolla (84-87) removed. · T3 BMW Z4 M Coupe model years corrected from 2007 to 06-08. · T3 Subaru STI 15-20 weight increases 150 lbs, to 3350. · T4 Volkswagen Passat, Jetta 1.8T adds 2014 model year to eligible years. · T3 BMW 323Ci/Is 98-00 minimum weight reduced from 3100 to 3000 lbs. · Subaru STI (15-20) newly classified in T3 at 3200 lbs minimum weight with 37mm turbo inlet restrictor required. · HP Toyota MR-2 1.6L (85-89) track corrected to 15.47 inches front and rear. · GT2 Mazda 13B street port adds EFR 70/76 turbo with 42mm restrictor at 2280 lbs. · GT3 Fun Cup Beetle EVO3 classified with 1984 cc sealed SOHC engine, 2060 lbs minimum weight. · GT2 Dodge Viper Comp Coupe ACR/ACR-X loses 100 lbs minimum weight to 3275. · Honda S2000 (00-03) reclassified as EP Prep with F22c engine option: 1997cc or 2157cc, weight 2450–2636 lbs depending on displacement. · EP Nissan 240-SX S13/S14 loses 200-210 lbs minimum weight; comp ratio rises to 12.0:1, valve lift to .500. · 04-06 World Challenge Pontiac GTO added to GT2-ST: 6062 cc, 3000 lbs minimum, unrestricted. · GTA part numbers updated: 0-80541-1 to 0-80541-2 in two sections and 6010 to 6014X in TA2 Appendix. · Grullon GT with 2.0L K20 moved from GTX to GT2-ST, minimum weight 2350 lbs, unrestricted. · EP Lotus/Caterham 7 America carburetor changed from IT fuel injection prep to fuel injection. · Daimler SP 250 classified in EP at 2165 lbs with 2548 cc OHV 8-cylinder engine. · GT2-ST Porsche Cayman restrictor increases from 65mm to 75mm flat plate at 2700 lbs. · GT2 Dodge Viper including Comp Coupe, ACR/ACR-X minimum weight reduced 100 lbs to 3275 in VRL Spec. · TA2 minimum weight set to 2930 lbs with free tire make and size. · STU fender flare wording clarified: exterior contour of any wheel opening may not change opening size, location or shape from side view. · STU Mazda 12A Bridge Port Miata weight reduced from 2550 lbs to 2350 lbs. · T3 Porsche Spec Boxster minimum weight reduced from 2600 to 2550 lbs. · T3 Porsche Cayman 06-08 wheel size changes from 18x8 to 18x9 inches. · T3 Mazda MX-5 Global Cup Miata ND2 with sequential gearbox allowed +100 lbs weight adder. · EP, FP, HP clarifies percentage weight penalties sum first, then apply to base weight, rounding to nearest pound. · T3 Honda Civic Type-R 2020+ allows brake rotor 45251-TGH-A01 with 25 lb penalty. · 84-87 Mazda 626 reclassified from FP to HP with 2300–2415 lbs weight, 1998cc SOHC, dual 32mm carbs. · FP Fiat X1/9 brake rotors change to 257 (10.1) x 12 (.407) solid disc. · EP Mazda MX-5 year range corrected from 06-14 to 06-15. · STU fender flare rules clarified: maximum 2 inches, must cover tire contact patch from above, cannot alter body configuration or wheel opening geometry. · T3 Porsche Boxster/Boxster S (00-04) now permits any OEM or aftermarket hardtop retaining OEM roof silhouette. · T3 Mazdaspeed3 07-09 and 10-13 now allow CorkSport Gen-6-999-10 or Autotech 10-127-100K fuel pumps. · Mazda 3 S 04-08 classified in EP at 2350 lbs minimum, 2.26L DOHC, 12.0:1 compression, .500" valve lift limit. · GT2 Sunbeam SBF 302 engine firing order option now explicitly allows Boss 302 variant. · STU Honda S2000 allows F20/F22 K24 crankshaft with chart weight for achieved displacement. · ST oil coolers and filters now explicitly allowed to be added or substituted; wording clarifies existing permissions. · T2-T4 clutch disc and pressure plate must be at least 95% of factory OEM weight. · Porsche Cayman 06-08 classified in T3 with 2687cc engine, 3050 lbs minimum weight, 18-inch wheels, 245 tires. · GT2-ST Corvette (-2019) LS2 and L76 5967cc gain 100 lbs minimum weight to 3100; 6162cc variants gain 50–100 lbs; 7011 gains 100–50 lbs; L76 restrictor opens 70 to 73 mm. · GT2 rear engine opening location requirement removed. · GT2 Ford Mustang/Thunderbird Boss 302 firing order now optional from later SBF 302 versions. · STL/STU 90-05 Mazda Miata gains approval for Mazda Motorsports Development alternate front wheel hubs. · T3 Ford Mustang EcoBoost gets 35mm TIR; Nissan 350Z DE Motor down 25 lbs to 3250; Mustang V6 down 50 lbs to 3475, restrictor tightened 55mm to 58mm. · GT2 ABS braking systems now allowed if shown on individual Spec Line. · GT2 Corvette C6 and C7 spec lines clarified and split; C7 LS2/L76/LS3/LT1/LS7 weights increased 100–150 lbs effective 3/1/2021. · ST cars may relocate ABS actuation hardware and wiring anywhere in engine compartment. · STU Porsche PDK automatic transmission limited to 8 forward speeds instead of torque converter restriction. · STU Mazda 13B Street Port 2400 removes choke location restriction, allows auto-type 2bbl with dual-Y manifold. · STU driveshaft and half-shaft materials change from OEM-type to steel or aluminum. · Toyota Supra 2020- newly classified in T2 at 3450 lbs minimum weight with 295 tire and 19-inch wheels. · T3 Chevrolet Camaro LT-I4 Turbo 1LE reclassified to 2016- model year, max tire size 275, TIR required 35mm. · T2 Ford Mustang GT 5.0L (15-17) gear ratios corrected to 3.66, 2.43, 1.69, 1.32, 1.00, 0.65 or 4.17, 2.34, 1.52, 1.14, 0.87, 0.69. · T3 Spec Boxster tire size increased from 225 to 245 DOT, permitting wider tires. · EP Austin-Healey 3000 Mk. I, II, III now allows TR-6 front calipers and discs as alternate. · GT2 Ford Mustang/Thunderbird Boss 302 firing order becomes unrestricted. · GT2 BMW E46 M3 weight reduced from 2600 to 2500 lbs. · STU Mazda 13B Street Port classified at 2400 lbs minimum weight, replacing peripheral and bridge port variants. · BMW M2 CS Cup 2020+ classified in T2 at 3625 lbs with 2979cc engine, 10.5x18 wheels, 295 tires. · T3 and T4 Mazda MX-5 06-15 now allow Mazda Transmission kit part # 0000-02-5700. · T2 and T3 Nissan 350Z and 370Z permit 44011-RC350 rear caliper kit and SZ350 rotors. · T4 Ford Mustang V6 05-10 allows GT 8.8 rear axle with 3.55 final drive, adds 25 lb penalty. · T3 and T4 FR-S, 86, and BRZ year ranges capped: T3 at 2021, T4 at 2017-2021. · FP Volkswagen Golf and Jetta 1.8 lose 50 lbs each, to 1900. HP Jetta GLI engine code removed. · EP, FP, HP Level 1 and Level 2 induction systems: clarified carburetor and fuel injection rules, jets/needles/rods unrestricted in Level 2. · EP Datsun SRL 311U Roadster minimum weight reduced to 1925 lbs from 2000 lbs. · EP Triumph TR8 78-81 weight reduced from 2600 to 2500 lbs. · GT2 Chrysler/Dodge/Plymouth 2429cc DOHC engine classified at 1950 lbs, unrestricted fuel induction. · ST aero devices and reference areas now include end plates but exclude fasteners protruding over 1/2 inch. · T3 Alfa Romeo 4C Launch Edition now allowed in Spec Lines. · HP 84-87 Toyota Corolla wheel diameter increases from 13 to 15 inches. · GT2 stock car bodies removal rescinded; 1997-current year commercially available stock car bodies remain allowed. · GT2 Appendix L renumbering eliminates sections .17 through .19 after 4.8.4.2.10.3.6. · GT2 TA2 wing width maximum set to 65 -5/16 inches, previously undefined. · Honda Civic Type R (2017-) classified in T3 at 3350 lbs with 1996cc engine, 245 max tire, 20-inch max wheel. · GT1, GT2, GT3, GTL, GTX now permit turbocharging/supercharging if listed on spec line. · GT2 Chevrolet Corvette -2019 LS1/LS6 allows DORMAN part # 615-900 alternate intake manifold. · GT2 Porsche 997.2 GT3 Cup minimum weight drops to 2900 lbs. · STU fender flare rules reworded: up to 2" per corner allowed with 1% weight penalty total. · EP BMW Z3 2.5L iron block casting 1738566-C designation removed, wording clarification only. · GT2 BMW E46 M3, E36, Z3, and 5000cc V8 gain Trans Am SGT spec allowance: regular shifter 3000 lbs., paddle shifter plus 150 lbs. · GT2 allows up to four hood/fender louvered panels, max 600 sq inches total, min five slots each, mounted in front of windscreen. · STL and STU clarify weight adjustment calculation order: engine adjustments first, then chassis adjustments. · STL and STU rear wing rules clarify that wicker is a Gurney flap; no performance change. · T3 Honda Accord (2009) V6 manual classified: 3471cc, 3450 lbs, 245 max tire, 19-inch wheels. · Porsche 911 S 67-68 classified in EP at three weight levels: 1800, 1845, or 1890 lbs. · TA2 Gurney flap wording clarified: terminology standardized to 'Gurney flap', height limits and thickness specifications remain 0.50 inch / 0.625 inch or 0.375 inch / 0.0625 inch depending on configuration. · STO rear wing wording clarified: 'wicker' changed to 'Gurney flap' in maximum chord and mounting height rules. · GT classes clarify Gurney flap wording, replacing wickerbill/tab terminology with flap; specifications unchanged. · STU request for alternate intake manifold denied; no rule change issued. · GT3 and STU add Borg-Warner EFR6258 to approved turbocharger list. · STU large displacement turbo engines limited by GCR turbo list; non-turbo trim suggested as more competitive. · STU sequential shifters referred to Board of Directors for approval; no change implemented yet. · T3 Mazda MX-5 Global Cup Miata ND2 2016-2019 must meet all ND2 Global Cup rules without appendix reference. · T3 VW GTI FSI gains turbo inlet restrictor allowance to 60mm, R32 brakes, Stoptech 4-piston kit, and Neuspeed intake options. · Cannot read: letter references external document #27663 not provided. · EP BMW 2.8L, 328i E36/E46, and 325i E36 blocks now iron only; 325i E46 aluminum only. · GT2 Dodge Viper 8400 OEM minimum weight drops 50 lbs to 3275. · GT2 Chevrolet Corvette -2019 OEM minimum weight cut 50 lbs to 3275. · STU Mazda 13B Bridge Port and Street Port engines added with 2550 and 2250 lbs minimum weights respectively. · 2004 Mercedes Benz CLK 320 Coupe classified in T4 at 3200 lbs with 3299cc engine and Eibach PN# 2563.140 springs allowed. · T3 Nissan 350Z Spec 2 DE Engine loses 57mm flat plate restrictor requirement. · 1990-1994 Mazda Protege classified in FP Pre at 2150–2258 lbs with 1839cc DOHC engine, fuel injection. · HP Mini Cooper model year ranges for convertibles revised: 02-06 now includes 05-08, 07-13 now includes 09-15. · GT2 Corvette LS6 may reduce weight by 50 lbs. · T3 Ford Mustang EcoBoost and V6 sway bars allowed up to 35mm front, 25mm rear. · T3 BMW Z3 M & Coupe 1998-1999 weight reduced from 3350 to 3150 lbs. · EP Caterham 7 Spec Line removes redundant suspension note, clarifies engine prep limits and comp ratio to 10.0:1. · GT2 Panoz GT-S now allowed to use TA2 Choice Engine with any 5-speed H-pattern transmission. · GT2-ST Corvette LS2 restrictor increases from 70mm to 75mm flat plate. · GT2-ST Corvette L76 added: 5967cc, 3000 lbs minimum, 70mm flat plate restrictor. · STU Honda S2000 adds HKS Supercharger kits 12001-AH006 and 12001-AH010 as allowed. · STU Lotus Elise Cup R and SC models, plus Exige SC, gain 100–200 lbs minimum weight. · STU Volkswagen GTI/GLI MK5 and Jetta Mk4 may install turbo inlet restrictor in OEM turbo inlet housing. · STU Honda K20C1 Turbo I4 restrictor reduces from 36mm to 35mm. · STU GM Ecotech LNF now allowed with turbo removed or with LE5 head and intake manifold, meeting STL specs. · STU Porsche 944 now permits VW/Audi 1.8L and 2.0L turbo engines as alternates. · EP BMW Z3 2.5L compression ratio capped 12.0:1, valve lift .500, 59mm restrictor required; Z3 2.8L same limits added; 944S2 compression 12.0:1, valve lift .500, 56mm restrictor required. · EP BMW 325is M-Technic loses 100–105 lbs across three weight configurations, to 2550–2678. · HP Datsun 510 gains 40 DCOE carburetor option alongside existing 40 DCN and 36mm DCNVH choices. · EP BMW fuel injected throttle body maximum inside diameter set to 64mm. · GT2 Porsche 991.2 GT3 Cup Car engine displacement increases from 3.8L to 4.0L. · STU vehicles over 2951 lbs base weight may use 9 inch wide wheels, up from 2950 lbs. · STU turbocharged engines now use base weight instead of minimum weight, with 3% DI increase applied to base weight. · T3 05-10 V8 Mustang allowed parts clarified: strut tower brace, radiator, springs to 500 lbs/in front and 300 lbs/in rear, sway bars, damper kit. · T3 Ford Mustang Coupe GT & Shelby GT 4.6L 05-10 adds permitted final drive ratios: 3.31, 3.55 or 3.73. · HP Datsun 1200 carburetor choke size increases from 26mm to 30mm. · GT1, GT2, GT3, GTL, GTX may omit windshield clips if factory glass is bonded per original specifications. · GT2 Chevrolet SS replaces Dodge Charger; all stock car bodies removed from GT2 in 2021. · BMW 330i 2006-2012 added to T3 with 2996cc engine, 3200 lbs minimum weight. · Pontiac Solstice GXP and Saturn Sky move from T2 to T3; wheels widen to 18 x 9.5 inches, Sky weight drops to 3200 lbs. · Mazda RX-8 Base/R3/Sport/GT (04-12) classified in T3 effective 2020-02-01. · T3 adds 2017 Ford Fiesta ST, 1596cc, 2600 lbs minimum weight, 245 max tire, 17x9 wheels. · FP and EP Mazda Miata models standardized to 55mm throttle body diameter; brake spec clarified. · Factory Five Type 65 Coupe R with Ford 302/351 or 5.0/5.2L NA added to GTX-MISC at 2600 lbs. · 991.2 GT3 Cup Car classified in GT2 at 3100 lbs with 63mm throttle body restrictor. · GT2 Acura NSX minimum weight reduced from 3000 to 2700 lbs. · GT2 Porsche 991.1 GT3 Cup restrictor size increases from 67 mm to 70 mm. · GT2 Porsche 996/997.1 GT3 Cup minimum weight reduced 100 lbs, to 2800. · GT2/ST Corvette -2019 5967cc restrictor reduced from 75 mm to 70 mm. · T2 requires onboard fire system; T3 and T4 may have one per GCR 9.3. · T3 Ford Mustang EcoBoost 2015- gains three transmission gear ratio options. · T3 Nissan 350Z and 370Z HR engines: restrictor plate enlarged from 37mm to 42mm, weight increased 50-100 lbs. · T3 Mazda MX-5 Global Cup Miata (2016-) tires now 215/610 R17 BF Goodrich G-Force Slick or wet; removes touring tire requirement. · T3 05-10 Mustang GT 4.6L suspension upgrades allowed: tower braces, radiator, 500/300 lbs/in springs, sway bars, dampers, control arms, shocks, driveshaft. · T3 BMW SpecE46 updates to SpecE46 rules Version 2.6 to 2.7, tire width to 225 maximum. · T3 Subaru WRX 02-05 minimum weight drops 100 lbs to 3250. · Mazda RX-8 Base/R3 (04-12) reclassified in T3 and T4 to include Sport and GT variants. · Toyota 86 GT (2017-) added to T3 and T4 Spec Line. · EP, FP, HP cylinder head rules reorganized for clarity; no performance change. · STU cars with manual OEM throttle bodies may convert to OEM electronic throttle body of same inner diameter. · T3 Scion FR-S/Toyota 86 and Subaru BRZ year range extended from 13-17 to 13-20. · T3 Mazda NC MX-5 gains two alternate six-speed and one five-speed transmission gear ratio option. · FP and HP Austin-Healey Sprite Mk I and MG Midget variants may replace rear bodywork aft of cockpit with stock-appearing alternate material components. · EP Mazda MX-5 Global Cup classification year changes from 16-18 to 16-19. · Production suspension rule clarifies spindles, hubs, bushings, bearings, ball joints unrestricted. · Production carb rules clarified: carburetor options, fuel injection throttle body dimensions, and intake manifold restrictions reorganised and refined. · EP, FP, HP carburetors clarified: jets, needles, metering rods, needle valves unrestricted; choke parts removable; permitted optional carburetors listed. · STU wing assembly wording corrected: no part higher than roof height. · T2-T4 spare tire/wheel rules clarified: removable covers can be removed with hardware and bracketry. · EP Mazda MX-5/Miata eligibility years expanded from 1999-2002 to 1999-2005. · T3 Mk7 GTI gains R32 brake package, 4-piston Stoptech kit to 355mm, and ECS street shield allowance. · GT2 TA2 cars must weigh minimum 2930 lbs per current Trans Am rules or prior Appendix L. · STU Nissan SR20DET removes -2mm penalty in Table B. · STU alternate intake manifolds now allowed case-by-case instead of prohibited. · T3 BMW E36 M3 96-00 allows alternate sway bars, 35mm front and 27mm rear. · GT2 Toyota Supra 3SGTE newly classified at 2900 lbs minimum weight, 43mm restrictor. · Acura NSX All Years classified to GT2-ST: 3.5L turbo, 3000 lbs minimum, 43mm restrictor. · GT2 TA2 minimum weight increases from 2830 to 2930 pounds. · STU aftermarket side skirts must meet 3-inch ride height, no openings except jacks or side exhaust, no wider than fascias, not higher than door bottom, no chassis reinforcement. · STU fender flare wording clarified: each fender may be flared up to 2" for tire clearance with 1% weight penalty. · 09-12 Porsche Cayman newly classified in T3 at 3150 lbs with 2900cc engine. · EP Mazda RX-8 firewall modification allowed for 13B engine fitment in stock location. · GT2 BMW E36/E46 4.5L V8 classified at 2950 lbs minimum weight. · GTX tube frame cars gain fuel injection with 90mm maximum throttle body size. · Ligier JS2 R classified in GTX, no performance parameters specified in filing. · STL and STU ride height measurement clarified: without driver, at rocker panel lowest point, excluding pinch weld. · T3 Chevrolet Camaro LT-I4 Turbo 1LE (2019-) classified with 1998 cc engine, 3450 lbs minimum weight, 245 max tire size. · T3 Honda Civic Si 2017- minimum weight reduced 100 lbs, to 2900. · Honda Civic Si 2017+ with alternate cage classified in T3 at 3075 lbs minimum weight. · T3 classifies 2014-2017 Volkswagen GTI with 35 mm turbo inlet restrictor, 3080 lbs DSG, 3050 lbs standard. · EP, FP, HP clarified: tapered holes in ball joints now allowed for bolt conversion; wheel bearings and hubs unrestricted at any wheel. · EP open cars may now use aftermarket hardtops if they retain OEM appearance; specific model hardtop allowances removed. · GT2 Ford Mustang 5.2L classified at 3300 lbs minimum with 82mm single throttle body restrictor. · GT1 and GT2/GT3/LITE ride height requirements removed from GCR sections 9.1.2.D.5.a.1 and 9.1.2.F.7.b. · STU Mazda 13B Bridge Port may use ELITE ROTARY SHOP FD V2.0 intake manifold instead of stock. · STU Mazda MZR LF/L3/L5 may use Goodwin Part #61-2510 intake manifold with stock or Acura throttle body. · STU suspension rules clarified: alternate components from same manufacturer moved from section E to section D. · STU Honda/Acura B20 classified at 1973 cc, now permits VTEC B16 or B18 cylinder head and intake manifold. · STU flared fenders up to 2" with 1% weight penalty moved from base to Advanced Aero rules. · TCA Honda Civic Si (2017-) must run 37mm TIR maximum as of June 1, 2019. · STU BMW S54B32 OEM reclassified from E46 designation, 3246 cc, 3300 lbs minimum weight. · BMW E36 M3 (96-00) BMWCCA I Sport newly classified in T3 at 3100 lbs minimum weight. · EP Mazda RX-7 12A and 13B (79-85) lose up to 80 lbs; 13B (86-91) loses up to 79 lbs. · GT2 Porsche Cayman model years change from 05-11 to 05-15. · GT2 Porsche Cayman adds 4.0L engine with 65mm flat plate restrictor at 2700 lbs minimum weight. · Honda Civic Si 2017- classified STU at 1500cc, 2800 lbs minimum with OEM engine and bodywork. · STU BMW E46 S54 OEM 3246cc added at 3300 lbs minimum weight, no Super Touring allowances. · STU Mazda 13B and 13B Bridge Port may use RE or REW housings and intake with turbo removed. · STU Honda K24 may use intake part #s 17100-RRB-A00 or 17100-PRB-A10. · STU Mazda 12A Bridge Port engine classified at 2550 lbs minimum weight with specified carburetor induction options. · STU World Challenge car weight calculation method removed; new basis unclear from text provided. · STU AWD cars no longer required to reduce restrictor 1 mm from table. · STU rear wing maximum cord length set to 12 inches, end plates to 72.0 square inches each. · T1-LP Ford Mustang GT 5.0L 2018+ classified at 3400 lbs with 65mm flat plate restrictor. · T3 Subaru WRX (2015-) classified at 3275 lbs with 35mm turbo inlet restrictor required. · T4 Mazda MX-5 Club (06-15) and (2016-), T3 MX-5 Cup and Miata (2016-) hardtop rules clarified; wording changes to permitted parts and specifications. · T3 Mazda MX-5 NC 06-15 wheel width increases from 17x7 to 17x8. · T3 Mazda MX-5 NC 06-15 now allows any aftermarket header. · T3 Saturn Sky intercooler tolerance increases from 32mm to 35mm TIR; new calipers and springs permitted. · T2, T3, T4 now allow any thermostat serving only OE intent, previously restricted. · T3 Subaru Legacy GT/Spec B 05-09 newly classified with 2457cc, 18×9 wheels, 245 tires, 3300 lbs. · T3 and T4 Mazda MX-5 Miata eligibility capped at 2018 model year, effective 2019-03-01. · T3 Mazda Mazdaspeed3 07-09 front brake disc increases to 320mm vented, rear to 300mm solid. · GT2 BMW E46 M3, E36, Z3, and 5000cc V8 now permit Flossman body kit. · GT2 TA2 cars: wheels cost cap drops to $175 each, carbon fiber allowed on rear wing, engine setback maximum 21.75 inches (A-F) or 24 inches (G), various nomenclature and clarification updates. · BMW 1 Series E82 classified into GT2 with N52B30 engine, 2996 cc, 2140 lbs minimum weight. · GT2 Porsche Cayman 05-11 base weight drops 75 lbs to 2800; adds STO/X51 motor notes. · GT2 Ford Mustang 05- with 5.2L Aluminator engine classified: 3400 lbs minimum weight, 2×41mm flat plate restrictor. · GT2 Porsche 996/997.1 GT3 Cup adds 3.6L displacement and 2900 lbs minimum weight; removes aftermarket exhaust header allowance for 996. · GT2 Ford Mustang FP350S minimum weight reduced 100 lbs, to 3400. · GT2 Ford Mustang 05- EcoBoost classified: 3500cc, 3200 lbs minimum, 41mm restrictor. · GT2 Mazda RX7 Downing GTS body kit allowed without 75 lbs. weight penalty. · GTX FIA GT3: Audi R8 40mm restrictor 2900 lbs, BMW Z4 70mm 2800 lbs, Ferrari 488 35mm restrictor 3025 lbs classified. · STU Honda K20C1 Turbo I4 1996cc added at 3025 lbs minimum weight with 36mm TIR. · T4 Ford Fiesta ST years corrected to 14-; T4 Fiat 124/Abarth Edition years added 16-18; battery rule clarified. · T3 BMW SpecE46 rules reference updated from Appendix N to Version 2.6 Effective Jan 1, 2019. · T3 Nissan 350Z Track/Touring/Standard/Nismo 03-08 permitted to use Nissan brake kit part number 41000-BRKIT. · T1-T3 spec cars receive clarifications on permitted modifications, documentation requirements, and rule conformance; no performance changes. · T2-T4 subframe bushings may now be replaced with non-spherical bushings of any material. · T3 field loses 50 lbs across 27 cars including Acura TL, BMW 335i, Camaro, Mustang, Miata, RX-8, 370Z, WRX. · T3 Ford Mustang EcoBoost gains Ford Motorsports or Brembo brake kit options, +100 lb. · T3 FR-S/86 and BRZ: wheels to 17x9, tires to 255, weight to 2750 lbs. · T3 BMW SpecE46 now permits any DOT tire up to 225 width as alternate to spec tire.showhide
EP Effective date for Jan 2025 GCR updates #37654inductionslowerEP BMW Z3 2.5L requires 52mm flat plate intake restrictor; Z3 2.8L 55mm; 328i/is E36 58mm; 328i/ci E46 58mm; 325i/is E46 56mm; 325i/is E36 56mm; 325is M-Technic 56mm.
GT2 GT2/ST - Remove Aftermarket/Racing ABS penalty #36538weightfasterGT2 STO aftermarket ABS weight penalty reduced from 100 lbs to 50 lbs.
T3 350z BOP #37427inductionfasterT3 Nissan 350Z HR Engine FPR restrictor increases from 47mm to 49mm.
T3 Request to Classify Club Spec in Appropriate Touring Classes #37523cars addedneutralFord SCCA Club Spec Mustang classified T3 at 3350 lbs with driver; Mazda SCCA Club Spec MX-5 classified T4 at 2500 lbs with driver.
EP Request to Reduce Weight of BMW 325i/is E30 (84-91) Spec Line #37119weight -50 lbsfasterEP BMW 325i/is E30 (84-91) weight reduced 50–52 lbs across three spec lines to 2150, 2204, 2258.
STU Audi 1.8t Wagon STU Table B #36685cars addedfasterSTU Audi 1.8T wagon deleted; Porsche 944 1800 weight to Chart, turbo inlet restrictor removed.
STU Merger GT3 to STU #37486wordingneutralSTU-GT3 reclassified as STU-GT3U effective January 1, 2026.
STU GT3 TCR Tire allowance #37494tyres & wheelsslowerSTU GT3 TCR gains 275-width tire option with 100 lb weight penalty, but not in A compound.
T3 Remove spec lines that have expired #37269removedneutralT2, T3, T4 remove nine, nine, and thirty-six expired spec lines respectively, effective 2025-01-01.
T3 Request to Move Spec Mustang to Touring 3 (from T2) #37080cars addedneutralFord Spec Mustang moves to T3 with 44mm bore restrictor, 275 max tire, 3450 lbs minimum weight.
T3 3.7 Mustangs BoP #37186inductionfasterT3 Ford Mustang V6 (11-14) and (15-17) now permit cold air intake.
EP Triumph GT6 Adjustments #37112inductionslowerEP Triumph GT6 switches to three Weber 40 DCOE carbs with 28mm chokes, weight rises 50 lbs to 1990.
STU Request to Remove Miata Hubs from General category #37138wordingneutralSTL/STU: 90-05 Mazda Miata alternate front wheel hubs moved from General to specific part approval.
STU BMW N54/N55 Engine Allowance #37146inductionslowerSTU BMW N54/N55 turbo inlet restrictors now required per GCR definition; turbo swapping prohibited.
T3 Amend TIR Placement on VW #36175wordingneutralT3 VW Golf R (12-13 and 15-18) 36mm TIR placement now allows OEM turbo inlet, removing 60mm distance limit from impeller.
T3 Redundant Verbiage Regarding Mustang Spec Lines for Driveshaft #36484wordingneutralT2 and T3 Mustang spec lines remove redundant driveshaft alternate/aluminum allowance wording.
T3 Fuel Emissions Components #37076wordingneutralT2, T3, T4 fuel cell installations may remove charcoal canisters, emissions valves, and sensors.
T3 fix brake wording #37129wordingneutralT2, T3, T4 brake component wording clarified: 2-piece rotors allowed in T2 within 5% OE diameter, T3 within 2% OEM diameter.
T3 Evaporative emissions systems #37130wordingneutralT2, T3, T4 fuel cell cars may remove charcoal canisters, emissions valves, and sensors.
T3 Allow Spec MX5 upgrade kit for 2009-11 RX8 S2 Transmision #37140wordingneutralT3 and T4 Mazda RX-8 and MX-5 permit transmission kit #0000-02-5700.
T3 Move Spec Boxster to T4 #37158cars addedneutralPorsche Spec Boxster moves to T4, minimum weight 2750 lbs, requires 3 Super Tour events before Runoffs eligibility.
T3 BMW 320i Spec Line #37204wordingneutralT4 BMW 320i 14-15 Spec Line expires 12/31/24 removed; Turner Motorsports intercooler #024703TMS02 allowed.
T3 Classification for a 2005 Cadillac CTS 3.6 liter 6 speed manual #37224cars addedneutralCadillac CTS 02-07 3.6L classified in T3.
T3 Request to Classify BMWs #37226cars addedneutralT3 BMW 328i/330i (06-12) model name updated; BMW 320i (14-15) newly classified at 3050 lbs.
T3 Make adjustments to the 2015 STI Spec line #37246tyres & wheelsfasterT3 Subaru WRX STI max model year extended to 21, max tire size increased to 275.
T3 class a civic #37294cars addedneutralT3 Honda HPD Civic Si FE1 newly classified with 1498cc engine, 18x8 wheels, 245 tires, 2950 lbs minimum weight.
T3 Older STI in T3 #37300weight -100 lbsfasterT3 Subaru WRX STI 03-07 drops 100 lbs to 3200; Legacy GT/Spec B 05-09 drops 150 lbs to 3200.
EP 1275 HP Spridget Level 2 Only #36518enginefasterHP Sprite and Midget 1275cc and 1098cc Level 2 compression ratio raised to 12.0:1.
EP NA Miata Track Width Correction #36902wordingneutralEP Mazda Miata front and rear track widths increased to 1516/1534 mm (59.7/60.4 in.) across all generations.
STU R53 15% Pulley Request #36980inductionslowerSTU Mini Cooper S SC 1900 restricts to 2.565 diameter pulley; 2100 allows 2.285 diameter pulley.
EP Errant entry in HP production line item #36231wordingneutralHP Volkswagen Golf and Jetta 85-92 track correction: front 1537mm (60.5in), rear 1529mm (60.2in).
STU RWD Turbo Disadvantage #36255inductionfasterSTU RWD turbo cars no longer required to reduce restrictor by 1 mm from table.
T3 Honda Civic Si (2017+) #36249inductionfasterT3 Honda Civic Si (2017-2021) restrictor removed, weight to 2950 lbs, Runoffs eligibility requires 3 Super Tour events.
T3 Subaru Reliability Help #36284wordingneutralT3 Subaru STI (15-20) and WRX STI (03-07) permitted to use OEM spec block #IAG-ENG-S550 and head studs.
T3 spec line for 36073 #36338cars addedneutralAudi TT Coupe 08-14 classified in T3 with 36mm TIR restrictor, 1984cc, 3200 lbs minimum weight.
T3 36131 #36339cars addedneutralT3 Mazda MX5 Miata/Club/RF (19-24) newly classified at 2550 lbs, 17x8.5 wheels, 245 tyres, 280 mm brakes.
GT2 GT4 cars may run in GT2-ST #36235cars addedneutralGT4 cars now permitted in GT2-ST with factory restrictor, must comply with 2012 STO rules, slicks allowed with 100-pound penalty.
T3 Mustang T2/T3 #35877wordingunclearFord Mustang GT 5.0L and V6 now permit Track/Performance Package parts in T2 and T3.
T3 T2-T4 Driveshaft Mistake...? #36050weightfasterT2-T4 Ford Mustangs: remove 25 lbs penalty for non-OEM driveshaft, clarify alternate driveshaft allowances.
T3 E&O: #35174 (Derek Chan) 350Z Parity Request #36116inductionfasterT3 Nissan 350Z DE engine now permits cold air intake.
T3 B8/8.5 Audi S4 T3 and T2 #36195cars addedneutralAudi S4 (2000-2002) moves to T3 with 3400 lbs minimum weight, 38mm turbo inlet restrictor required.
T3 Z4 Roadster Eligibility #36196cars addedneutralT3 BMW Z4 3.0si expands to include 3.0i Roadster and Coupe (07-08); hardtop permitted with positive fasteners.
EP NIssan 300ZX Z31 to EP #35830cars addedneutralNissan 300ZX 84-89 classified to EP at 2550 lbs minimum, 2960cc 6-cyl SOHC, fuel injection, 12.0:1 compression limit, 0.500" valve lift limit.
EP RX7 1993 and Up Request In EP Spec Lines, classify #36031cars addedneutralMazda RX-7 92-97 newly classified EP Prep Level 2 at 2200–2310 lbs with 13B 6-port rotary engine.
EP Clean-up Multiple EP RX-8 Spec Lines In EP #36156wordingneutralEP Mazda RX-8 (04-11) alternate spec line removed; one primary line remains.
T3 Global MX5 Tre change #36046tyres & wheelsunclearT3 Mazda MX-5 Global Cup Miata ND1/ND2 tire size changes to 225 DOT specification.
GT2 Request for Spec Line 1010 Reconsideration #35009weight +300 lbsslowerGT2-ST Acura NSX minimum weight raised to 3000 lbs, restrictor increased to 45mm TIR.
GT2 Request to Eliminate the FPR from the Corvette (-2013) with LS2 #35878inductionfasterGT2-ST Corvette 14-19 LS2 restrictor increases from 78mm to 80mm flat plate.
T3 Allow T4 and T3 RX8 to Disable/Remove Factory Oil Inj. #35761engineunclearT3 and T4 Mazda RX-8 may remove or disable factory oil injection system.
T3 Driveshafts #35916weightslowerT2, T3, T4 driveshafts may use alternative materials or one-piece units; non-OEM adds 25 lbs.
T3 Audi S4 HST requirement #35918wordingneutralAudi S4 00-02 in T3 must compete in 3 Super Tour events before Runoffs eligibility.
EP GCR Correction - Redundant HP Spec Lines #35623wordingneutralHP removes four redundant VW spec lines: Rabbit Cabriolet 1780, Scirocco 1588, Scirocco 1780 8-valve, Scirocco 1588.
GT2 Classify Corvette C8 (2020- ) into GT2/ST #33759cars addedneutralChevrolet Corvette C8 (2020–) classified into GT2-ST with 6162cc displacement, 3300 lbs minimum weight, 71mm restrictor.
GT2 Requesting classification for a 2015 Mitjet ST in GT2 #35408cars addedneutral2015 Mitjet ST added to GT2, must run per VTS specifications with complete FIA form CdM008.
STU Letter #35397 addendum #35453wordingneutralSTU Mini Cooper S SC: alternate LEAP OMICRON hood scoop LEP-OMICRON3 permitted.
STU S54 Drysump #35464wordingneutralSTU BMW S54 B32 OEM now permits dry sump oiling system.
T3 Spec Z Interchange in T3 #34416tyres & wheelsfasterT3 Spec Z 350Z rear wheel width increases to 10 inches; HR Engine restrictors change from 42mm to 44mm.
T3 please classify 2000-2002 Audi s4 #35306cars addedneutralAudi S4 2000-2002 classified in T3 at 3400 lbs with 38mm turbo inlet restrictor required.
T3 Reorganize Spec Lines #35375wordingunclearT2-T4 Spec Lines remove wheelbase requirement, replace with Required Restrictor specification.
T3 370Z Brake Rotor Size Correction #35487suspension & brakesneutralT2 and T3 Nissan 370Z brake rotors enlarged: front 320x28 to 355x32mm, rear 320x16 to 350x20mm vented.
T3 T3 V6 Mustang help #35526enginefasterT3 Ford Mustang V6 (11-14) restrictor requirement removed; (15-17) brake penalty reduced to +50 lbs from +100 lbs.
T3 Nissan 370Z - Brake System Allowance - Brake Booster #35556suspension & brakesneutralT3 Nissan 350Z and 370Z now allow brake booster vacuum regulator, must not be in-car adjustable.
T3 Mustang Help #35559inductionfasterT3 Ford Mustang 4.6L restrictor holes increased from 40 mm to 45 mm.
T3 Appeal for Retention of T3 Mazda RX-8 Spec Line (Letter #35378) #35577wordingunclearT3 Mazda RX-8 Spec Line retention appeal directed to letter #35584 for ruling.
T3 Request to Keep the Mazda Rx-8 in Touring 3 #35584wordingneutralMazda RX-8 04-12 expiration date removed; no longer expires 12/31/24.
T3 Subaru WRX (02-05) Appeal #35656wordingneutralT3 Subaru WRX (02-05) spec line expiration deadline removed; class now permanent.
EP Update 1988-1991 Civic to Match 1988-1991 CRX #35399weightfasterHP Honda Civic 1.5 (88-91) weight reduced to 2175 lbs base, 2229 lbs with power adder, 2284 lbs with two.
GT2 Rear Blade Spoiler Clarification #35261aerofasterGT1, GT2, GT3, GTL, GTX rear spoiler maximum surface area limit of 295.0 square inches removed.
GT2 GT Direct Injection allowance and rules #35437enginefasterGT1/GT2/GT3/GTL/GTX Direct Injection now permitted if OE, using only OE pump, hoses, injectors.
GT2 REDUCE C6 CORVETTE WEIGHT WITH OEM 7 LITER ENGINE REDUCE BY 150LB #35385weight -150 lbsfasterGT2 Chevrolet Corvette 7011 OEM 7 liter weight reduced 150 lbs, to 3125 lbs.
GT2 GT2/3 remove Direction Injection not allowed in Spec line notes #35439inductionfasterGT2/3 Nissan, Mazda, Mitsubishi 4G93, QR25DE/DD, QE25DE/DD Direct Injection now permitted per 9.1.2.F.7.5.E.
STU ST Electric-Assisted Steering Systems #35066wordingneutralSTL and STU power steering rules clarified to permit electric-assisted and hydraulic-assisted steering systems.
T3 15-18 Golf R Alignment with Existing GTI and R Speclines #35235tyres & wheelsfasterT3 Golf R 15-18 max wheel width increases to 9 inches, max tire size to 255.
T3 More Car Lightening Stuff #35319weightfasterT2, T3, T4 battery replacement wording simplified; OEM weight tolerance requirement removed.
T3 Open Strut Tower Brace Options for Ford Mustang V6 (11-14) #35322wordingneutralT3 Ford Mustang V6 (11-14) gains approved strut tower brace and sway bar kit options.
T3 Mustang ecoboost #35351inductionfasterT3 Ford Mustang EcoBoost 2015- intake restrictor increases from 35mm to 36mm TIR.
T3 Inclusion of B-C spec cars in T4 #35374cars addedneutralT4 now permits C-Spec cars to compete alongside B-Spec cars.
T3 T2-T4 Set expiration dates on spec lines #35378wordingneutralT2-T4 spec lines for 46 cars expire 12/31/24; appeal required to continue.
EP Request to Review Z3 2.5 Spec Line #35073weight +50 lbsslowerEP BMW Z3 2.5L weight increases to 2500 lbs, 2563 lbs with turbo, 2625 lbs with supercharger.
EP Miata Alternate Head #35253weight -50 lbsfasterEP Mazda MX-5 1.8L 1990-97 minimum weight drops to 2150 lbs; 1994-97 variants to 2000, 2050, 2100 lbs respectively.
EP Honda S2000 throttle body #35272inductionfasterEP Honda S2000 fuel injected throttle body inside diameter increases from 62mm to 64mm.
EP Correction within Triumph TR8 Spec Line #35315wordingneutralEP Triumph TR8 dry sump allowance moved from carburetor line to notes section.
EP Correction to EP 924S/944 Spec Line #35317wordingneutralEP Porsche 944/924S 2.5L and 2.7L weight minimums corrected: 2479cc to 2306/2363 lbs, 2681cc to 2358/2415 lbs.
GT2 Dodge Viper Gen 3 hybrid Kit Update Request #35200inductionslowerGT2-ST Dodge Viper hybrid kit restrictor reduced from 50mm to 45mm flat plates.
T3 T3 Solstice Brakes #35106suspension & brakesslowerT3 Pontiac Solstice GXP front brake rotor increases from 296 to 355 mm vented.
T3 350Z Parity Request #35174weightslowerT3 Nissan 350Z DE motor loses 75 lbs to 3125; HR motor gains 47mm restrictors, up from 44mm.
T3 Requested Update of Model Years of 370Z #35231wordingneutralT3 Nissan 370Z model years expanded to include NISMO Edition through 2022.
T3 Update Request for 2010 Mustang GT 4.6 #35234wordingneutralT3 2010 Mustang GT 4.6 now allows 2013-14 GT style front/rear fascia, hood, and associated assemblies.
T3 SE46 Continued Parity/ Cold Air Intake request #35267weight -50 lbsfasterT3 BMW SpecE46 minimum weight drops 50 lbs to 2850.
T3 Please help the Subaru STIs. #35278weight +100 lbsslowerT3 Subaru STI (15-20) minimum weight increases 100 lbs to 3450; all three STI variants get larger turbo inlet restrictors.
EP Porsche 944/924S Rule Change Request #35002cars addedneutralEP Porsche 944/924S combines 2.5L and 2.7L variants with new weights: 2250–2415 lbs depending on engine and year.
EP Triumph GT6 Adjustments #35054weight -30 lbsfasterEP Triumph GT6 minimum weight reduced to 1800 lbs.
GT2 Errors in GTCS Headings and Use of the Terms Category and ClassChange existing GTL and GTA Rules #34453wordingneutralGTL spec lines moved to contiguous position with GT2 and GT3; GTA category and spec lines renumbered and moved behind GTL.
T3 Porsche Cayman Transmissions and Ratios #34891wordingfasterT3 Porsche Cayman (09-12) and (13-16) gear and final drive ratios adjusted; 09-12 6-SPD final drive 3.88 to 3.875, PDK 3.909 to 3.250; 13-16 6-SPD final drive 3.89 unchanged, PDK 3.91 to 3.250.
T3 2006-10 Volkswagen GTI - Weight Reduction request and KO4 Turbo #34414inductionfasterT3 Volkswagen GTI 06-10 turbo inlet restrictor increases from 36mm to 37mm.
T3 Adding Model Years to T3 Golf R Spec Line #34612wordingneutralT3 Volkswagen Golf R permitted model years extended from 15-16 to 15-18.
T3 Rear Camber Arms for T3 VW Golf R #34613wordingneutralT3 Volkswagen Golf R 15-16 now permits Verkline WAS-048 camber arms.
T3 Classing Spec E90 Cars in SCCA #34791cars addedneutralBMW Spec E9X classified in T3 at 2975 lbs, must conform to SpecE9X rules Version 2.10, tire max 225.
T3 TIR location requirement in VW Golf Spec lines #35048wordingneutralT3 VW Golf GTI and Golf R TIR location clarified to maximum 60mm from impeller.
GT2 Late E & O #34966weightfasterGT2-ST Dodge Viper including Comp Coupe, ACR/ACR-X with VRL front fascia loses 100 lbs.
EP Hub Note Clean Up In EP TR8 Spec Line #34649wordingneutralEP Triumph TR8 78-81 removes alternate front hub allowance note; stock hubs now required.
EP Triumph GT6 Adjustments #34662wordingunclearEP Triumph GT6 carburetors change from SU or Stromberg to 1.5" Auto-type.
EP Triumph GT6 Adjustments: Brakes #34663wordingneutralEP Triumph GT6 brakes may now use TR-6 standard or alternate calipers and discs.
GT2 GT2 Mazda 20B 3 rotor ENO #34765weight -220 lbsfasterGT2 Mazda 20B 3 rotor loses 220 lbs, to 2280, consolidating two spec lines.
T3 2012-2013 Golf R - added to T3 #34413cars addedneutral2012-2013 Volkswagen Golf R added to T3 as new entry with 1984cc engine, 3080 lbs DSG/3050 STD, 36mm turbo inlet restrictor.
T3 Rules Clarification for Mazda RX8 Spec Line #34395wordingneutralT3 Mazda RX-8 removes transmission/final drive pairing requirement; T4 removes same requirement, adds Mazdaspeed radiator and coil spring kit.
T3 rule book corrections #34437otherfasterT3 BMW 320i (14-15) gains aftermarket intercooler permission; T4 loses it.
T3 Allowing 255 Tire Width for Nissan 350z #34471tyres & wheelsfasterT3 Nissan 350Z and 370Z maximum tire width increases from 245 to 255.
T3 Ride Height Correction for the T3 Solstice. #34615wordingneutralT3 Pontiac Solstice GXP minimum ride height set to 3 inches.
EP Correct Intake Valve Size on 1500cc Midget/Spitfire #34419wordingneutralFP and HP Sprite, Midget, and Spitfire 1500 intake valve size corrected to 36.6/(1.44).
GT2 appendix letter #33635 #34206wordingneutralGT2 BMW engines: 3.4L 6-cyl at 2575 lbs, 4.0L V8 at 2900 lbs, 4.5L V8 at 2950 lbs, 5.0L V8 at 3000 lbs; S54 with 97mm stroke permitted at 2800 lbs.
GT2 Remove Weight and Restrictor Penalty for Corvette C7 Body #34342inductionfasterGT2 Corvette C7 restrictor increases from 73mm to 77mm flat plate, removing weight penalty.
STU 2022 Toyota GR Cup for STU #34449cars addedneutralToyota GR Cup and GR86 Cup (2022-) newly classified in STU at 2700 lbs with 2387 cc engine.
T3 2016+ Camaro 1LE - Max Wheel Diameter #34003tyres & wheelsfasterT3 Camaro V6 1LE and LT-I4 Turbo 1LE max wheel diameter increases from 18 to 20 inches.
T3 2022 Toyota GR Cup for T3 #34448removedneutralT3 removes Toyota 2022-up GR Cup and 2022-up GR86 Cup entirely from Spec Lines.
EP 914-6 Valve Size Correction #34185enginefasterEP Porsche 914-6 2.0L intake valves increase to 2.0 mm, exhaust valves corrected to 38.0 mm.
T3 S550 Reconcile With S197 #34093weight -75 lbsfasterT3 Ford Mustang V6 (15-17) weight drops to 3400 lbs, brake penalties reduced to +100 lbs and +50 lbs.
T3 SE46 Parity Help #34178weight -50 lbsfasterBMW SpecE46 in T3 loses 50 lbs, to 2900.
T3 2022 Toyota GR Cup for T3 discussion #34234cars addedneutralT3 adds 2022 Toyota GR Cup and GR86 Cup, both 2387cc, 2700 lbs, 245/620R18 slicks, 332x32F/280x32R brakes.
GT2 Request to class 2011 Porsche Cayman S #33771cars addedneutral2009-2012 Porsche Cayman S classified in GT2, 3.4L, RWD, no PDK transmission allowed.
GT2 Please classify Fields Cardinal V8 #33784cars addedneutralFields Cardinal V8 classified in GT1 with Ford V8 engine, 4.9L displacement, 2100 lbs minimum weight.
T3 Request Spec E46 in T3 Weight Adjustment #33897weight -25 lbsfasterT3 BMW Spec E46 weight reduced 25 lbs, to 2925.
T3 E36 2.5L 323is Weight Reduction #33975weightfasterT3 BMW 323Ci/Is weight reduces to 2750 lbs from 3000 lbs.
T3 Update SpecE46 Spec Line to Current SpecE46 Ruleset #34016wordingunclearT3 BMW SpecE46 must conform to SpecE46 rules Version 2.10, updated from 2.7.
EP Investigate Parity of Z3 #33343inductionslowerEP BMW Z3 2.5L intake restrictor reduced from 58mm to 56mm flat plate.
GT2 Adding Ginetta G56 GTA Factory ProTune for GT2 Class #33825wordingunclearGT2 Ginetta G56 GTA may now use Factory installed ProMap ECU Map.
STU Alternate OEM Miata Intake Manifold #33827wordingneutralSTU Mazda BP5A classified at 1839 cc maximum displacement, 2023-04-01.
T3 Request to all ECS Tuning inner-cooler to 06-10 VW GTI spec #33769wordingneutralT3 06-10 VW GTI, Jetta GLI allowed to use ECS Tuning performance alternative intercooler.
STU E&O STU NA Weight Chart. #33737weightfasterSTU minimum weight chart updated: 2450cc to 2595lbs, 2600cc to 2710lbs.
T3 T3 Boxster S GCR request #33687wordingneutralT3 Porsche Spec Boxster tire rule updates to current SPB rules or any 245 DOT tire.
T3 OEM VW Steering Spindle Replacements 06-10 VW GTI and Jetta #33732wordingneutralT3 06-10 VW GTI and Jetta permitted to use OEM VW knuckles 3C0407253F and 3C0407254F.
T3 BMW 320I intercooler #33762otherfasterT3 BMW 320I now permitted to use aftermarket intercooler.
GT2 GT2 Mazda 13B Turbo #33729engineunclearGT2 Mazda 13B Street Port turbo changes from EFR 76/70 to BW7670 or Garrett G30-660 with 46mm TIR at 2280 lbs.
T3 Request to classify 2014 Base Cayman #33159cars addedneutralPorsche Cayman (13-16) classified in T3 at 3225 lbs with 2700cc engine, 18x9 wheels, 245 tires.
T3 Mustang OEM Grill Request #33333aeroneutralT2/T3 Mustang GT 5.0L and V6 (11-14) may remove upper grille fog lights, replace with mesh or screen.
T3 Hyundai Classification #33498cars addedneutralHyundai Veloster Turbo 2018-2021 classified in T3 at 3050 lbs with 1584cc engine, 245 max tire size, specific suspension and brake modifications allowed.
T3 Adjustable Rear Camber Arms for VW (All Generations) #33572wordingneutralT3 Volkswagen GTI and Jetta GLI now permit Verkline WAS-048 adjustable rear camber arms.
EP Revise 79-85 RX7 Brake Spec Line Allowance #33293wordingunclearEP 79-85 RX-7 12A/13B brake spec simplification removes hub/rotor weight minimum allowance.
EP Request alternate carburetors for EP 280z #33405wordingneutralEP 280Z carburetor option adds Hitachi-SU 1bbl 46mm throttle bores alongside fuel injection.
EP Fuel Injection 12a Mazda RX3 #33434inductionneutralEP Mazda RX-2, RX-3, RX-4, and 12A RX-7 now allow 2 bbl fuel injected throttle body w/ 42mm chokes on dual-y manifold.
EP Mazda RX3 - Weight Reduction #33436weight -50 lbsfasterEP Mazda RX-2, RX-3, RX-3SP, and RX-4 minimum weights reduced 50–52 lbs across all spec lines.
EP Request TR8 Dry Sump Allowance #33460enginefasterEP Triumph TR8 78-81 now allowed to run dry sump.
EP Review Limited Prep Port Matching Rules #33600wordingneutralEP, FP, HP cylinder head ports limited to 1 inch maximum depth matching from mating surface.
EP 280ZX Classification Request #33611cars addedneutralEP Prep 280ZX (79-83) added to spec lines with 2425–2546 lbs, 2760cc SOHC 6-cyl, fuel injection, 12.0:1 compression limit, .500" valve lift limit.
GT2 Request Permission to Use a Substitute Turbo #33337inductionfasterGT2 Porsche SOHC 2478/2681/2992 turbo sizes increase from 42mm to 44mm SIR to TIR.
GT2 Request to Reduce Restriction on C7 GT2 Corvette #33342inductionfasterGT2-ST Chevrolet Corvette 14-19 L76 5967 restrictor increases from 70 to 73 mm.
GT2 Toyota 4A-F and 4A-FE 1.6L DOHC 16V Engine Request #33415cars addedneutralGT2 Toyota 4A-F and 4A-FE 1.6L DOHC 16V engines newly classified in spec line.
GT2 GT2 Mazda 13b turbocharger part # update #33437enginefasterGT2 Mazda 13B Street/Bridge Port turbocharger changes from EFR 70/76 to 76/70, compressor from 42mm to 46mm.
GT2 GT2-ST BMW E36/46 spec line remove #33610wordingneutralGT2-ST BMW E36/46 spec line adds MA Shaw carbon/composite door offerings to Notes.
GT2 GT3 Choke option effective 1-01-2023 #33669inductionneutralGT3 normally aspirated cars may use intake chokes instead of SIRs, fitted to each carburetor barrel, same size as required SIR.
GT2 GT3 2.0L choke/weight option #33670inductionfasterGT3 2.0L 4-valve non-turbo engines may run unrestricted at 2060 lbs instead of with a choke restriction.
T3 350z SPC Upper Control Arm Safety Concerns #33020suspension & brakesneutralT3 Nissan 350Z and 370Z remove SPC Control Arms 72130, 72125, 72123; permit performance alternative front upper control arms.
T3 Request Help for 350z #33379weight -100 lbsfasterT3 Nissan 350Z loses up to 75 lbs and gets 44mm restrictors; 370Z loses 100 lbs. Wheels widened front and rear.
T3 Ecoboost Acknowledgement #33506inductionfasterT3 Ford Mustang EcoBoost 2015- turbo inlet restrictor increases from 34mm to 35mm TIR.
T3 Touring (T2-T5) Category #33617cars addedneutralT5 class added as regional-only; T5 tyres maximum width 225, minimum aspect ratio 45.
T3 ENO 9.1.9.2.D.1.e.1.a. #33651suspension & brakesneutralT2-T5 Touring front and rear suspension maximum negative camber changed to 3.5 degrees.
GT2 GT2 (TA2)/GTA Part Number Update #33315wordingneutralGT2 TA2 and GTA throttle body part numbers updated to GM 90mm electronic #12570790 or Edelbrock 90mm mechanical #33869 or #3870.
GT2 Ginetta G56 GTA - Optional Wheels #33357tyres & wheelsneutralGT2 Ginetta G56 GTA gains optional 18" x 9" and 18" x 10" wheels.
T3 Solstice GXP in T3 #33501wordingneutralT3 Solstice GXP intercooler options expanded: Hahn HIC-1150 or Dejon FIC-SSA replaced with Performance alternative.
GT2 Allow the MAShaw Body Kit on the GT2/ST Spec Line for BMW E36/E46 #32447aerofasterGT2/ST BMW E36/E46 now allows MAShaw body kit parts: wide body, bumpers, fenders, rockers, flairs.
GT2 Request for C5/C6 Corvette Restrictor Size Review #32982inductionfasterGT2 Chevrolet Corvette L76 5967 restrictor increases from 73mm to 74mm.
T3 Another 2022 BRZ/86 T3 request #32945weight +225 lbsslowerT3 Subaru BRZ 2022- minimum weight up to 2975 lbs; spring rate to 1000 F/R, brake parts allowed without penalty.
EP Request to classify VW New Beetle 2.5L in EP #32725cars addedneutralVW New Beetle 2.5L 5-cyl added to EP at 2400–2520 lbs, 2480 cc, fuel injection, comp ratio 12.0:1 max, valve lift 0.500" max.
EP Request Rotary Injection on Dual Y manifold #32775inductionunclearEP Mazda RX-7 12A/13B gains fuel injection option on dual-y manifold with 42mm choke(s).
EP Request for Corrado Stroke & Displacement Correction #32985wordingneutralEP VW Corrado 92-95 stroke corrected to 90.3 mm, displacement to 2792 cc.
GT2 Tail lights on all GT category race cars. #32799wordingneutralGT taillights may now be original style or a panel graphic with functioning red LED brake lamps; wording change only.
GT2 Addendum to letter #32514 Ginetta GTA G56 #33076cars addedneutralGinetta GTA G56 added to GT2 as spec car: 2600 lbs, 3.7L Ford V6 sealed, 6-speed Quaife sequential.
T3 S2000 Hard Top Clarification #32779wordingneutralT3 Honda S2000 hardtop clarified: OEM, Mugen P/N 0000-04-2312, or aftermarket permitted if OEM roof silhouette retained.
T3 T3 Pontiac Solstice- #33081tyres & wheelsslowerT3 Pontiac Solstice GXP Coupe/Convertible 07-09 tire runout increases from 35mm to 36mm TIR.
GT2 Information requested for carbon roofs on BMW E36/E46 cars in GT2 #32682wordingneutralGT2 BMW E36/E46 carbon roof and door suppliers added to notes: Lang Racing, 2M Automotive, Flossmann, MA Shaw.
GT2 Request to Allow the 95mm S54 BMW Crankshaft in GT2-ST #32698weightslowerGT2-ST BMW E46 M3, E36, Z3, 5000cc V8 can use 95mm S54 crankshaft at +150 lbs.
GT2 Request to classify Audi R8 FIA GT4 to GT2 #32805cars addedneutralAudi R8 GT4 classified to GT2 with 5.2L displacement, 3000 lbs minimum weight, per factory specs restrictor.
STU Request Mazda 13 B turbo #32668cars addedneutralSTU Mazda 13B Turbo classified, streetport only, stock turbos prohibited, alternatives allowed.
STU Hood Vents and Intercooler Scoops #32733aerofasterSTU OEM louver vents now exempt from vent count and 200 square inch allowance.
STU Non 4 valve weight reduction removed #32808enginefasterSTU 2400cc non-4-valve engines gain 9% base weight reduction; DI turbo prep limits removed.
STU Error in new minimum weight table when combined with other text #32711engineslowerSTU normally-aspirated 2976–3200 cc single-throttle engines lose 10% base engine weight reduction.
STU Redundant Language in May GCR #32713wordingneutralST redundant language removed from balance shaft and pulley modification rules.
T3 Classify Car #32691cars addedneutralBMW 320i (14-15) classified in T3 at 3050 lbs with 18-inch wheels, 255/275 tires, 3.08 final drive.
T3 2022 BRZ Sway bar and lip spoiler. #32703suspension & brakesfasterT3 Subaru BRZ (2022-) and Toyota GR86 (2022-) permit 25mm front and 22mm rear sway bars, OEM trunk spoiler.
EP Subaru BRZ Model Years #32500wordingneutralEP Subaru BRZ and Toyota 86/Scion FR-S model year ranges updated to 13-20.
EP EP MX-5 Global Cup Car #32218weightslowerEP Mazda MX-5 Global Cup 16-22 minimum weight set to 2400 lbs; sequential gearbox allowed with +150 lbs penalty.
EP Please Class BMW 128i in EP #32370cars addedneutralBMW 128i (08-13) classified in EP at 2700 lbs minimum with stock throttle body, 11.0:1 compression ratio, 0.400 in. valve lift limits.
EP Inconsistency in Body Work Descriptions #32396aerofasterEP/FP/HP open cars may now use carbon fiber hardtops if they retain OEM appearance in all exterior profiles.
GT2 Typo in rules for shocks #32308wordingneutralGT2 shock absorber attachment points clarified as moveable; wording correction only.
GT2 additional response to letters #31898 & 32083 #32424weight +140 lbsslowerGT2 Porsche 104.0 x 88.0 engine weight increases from 1950 to 2090 lbs; 2V variants may use Borg Warner EFR 76/70 42mm turbo.
STU Opposed to the Proposed STU Weight Chart #32381wordingneutralSTU cars that qualified for 9 inch wheels in 2021 may continue through 2022 only.
STU Clarification request for GCR 9.1.4.D.3.a Splitter Definition #32414wordingneutralSTU splitter definition clarified: must be single-plane with no vertical deviations, attached to lowest front point.
T3 correct wording #31750wordingneutralT3 Honda Civic Si (2017-) spec clarified: wheels to 10" wide allowed with 50 lb. penalty, 1-piece rotor required.
T3 2005-2008 Porsche Boxster 2.7 #31999cars addedneutralPorsche Boxster Base 2005-2008 newly classified in T3 at 3000 lbs minimum weight.
T3 Request Alternate Front & Rear Strut/Shock Top Hats #32452suspension & brakesneutralT2-T4 Touring cars with alternative springs may use performance top hats with spherical bearings on shocks and struts.
T3 2022 Subaru BRZ and Toyota 86 twins #32483wordingneutralT3 Subaru BRZ and Toyota 86 (2022-) wheel size corrected to 18 x 8 in., gear ratios and final drive specified.
EP Mazda RX8 with 13b Rotary #32170wordingneutralEP Mazda RX-8 13B carburetor rules clarified: dual 2bbl carb, fuel injected throttle body, or stock fuel injection permitted.
EP Request Idle control valve clarification #32178wordingneutralEP and FP Production clarifies idle control valve rules: stock devices allowed original, removed with blocked ports, or mechanical replaced with electronic stock type.
STU Request Adjustment to Min Weight for STU BMW E36 M3 (95-99) #31535weight -90 lbsfasterSTU BMW S52B32 minimum weight drops 90 lbs to 3110; max displacement cut to 3152 cc.
STU BMW E36 M3 Canadian (North American) S50B32 engine #31866cars addedneutralSTU BMW S50B32 Euro classified at 3201 cc displacement, 3300 lbs minimum weight.
STU Engine Swap Origin Country #32209wordingneutralST engine swap origin country requirement changes from North America to the United States for case-by-case approval.
STU CRX/Civic Del Sol #32214weightslowerSTU Honda CRX (84-91) and Civic Del Sol (93-97) ineligible for front wheel drive weight reductions.
STU Error correction #32383tyres & wheelsfasterSTU vehicles at or over 2950 lbs base weight may use 9 inch wide wheels instead of 8.0 inch maximum.
STU Single TB Weight Modifiers Add to Chart #32393weightfasterSTU minimum weights reduced: 2450cc to 2596 lbs, 2500cc to 2635 lbs, 2550cc to 2675 lbs.
T3 Request to Allow the Use of Aftermarket ECU's in Touring #31067weightslowerT2-T4 cars model year 2018+ may use non-OEM ECU with 75 lb weight penalty via spec line adjustment.
T3 T3 Mustang V8/V6 #31959weight -50 lbsfasterT3 Ford Mustang V6 (11-14) minimum weight reduced to 3350 lbs.
T3 Subaru STI (15-20) Missing part #32294suspension & brakesneutralT3 Subaru STI 15-20 now allows SPC lower control arm 67660.
EP EP Adjustments #31858inductionslowerEP BMW Z3 2.5L intake restrictor reduced from 59mm to 58mm flat plate.
EP 1999 3.8L Ford Mustang to EP? #31635weightfasterFord Mustang 99-03 classified to EP at 2700/2768/2835 lbs; 94-98 Mustang weight reduced to 2550/2614/2678 lbs.
EP Improved Touring Tires #32064tyres & wheelsneutralEP, FP, HP Improved Touring cars may use any DOT-approved tire per section 9.3.45 in Production class.
GT2 Request to Classify Ginetta G40 in GT2 #31597cars addedneutralGinetta G40 classified in GT2 with Mazda MZR/L5-VE engine, 2488cc or 2399cc, 1950 lbs base weight.
GT2 2021 Supra GR GT4 #31737cars addedneutralToyota Supra GT4 added to GT2-ST: 3000cc, 3000 lbs minimum, factory restrictor.
GT2 Proposed Technical Bulletin #31900wordingunclearGT2 Porsche 944/924 may use ERC 76/70 Turbo instead of Jayco super 50.
STU Single TB Weight Modifiers #31449weightfasterSTU normally aspirated engines: minimum weights reduced up to 310 lbs; single throttle body weight reduction removed.
STU Request to Remove A4 1.8t from STU Spec Line Tables #31465weightslowerSTU Audi A4 1.8T minimum weight fixed at 3050 lbs, VF30 turbo with 35mm restrictor now required only.
STU Improved Touring Tires #32063tyres & wheelsneutralSTL and STU Improved Touring vehicles must conform to 9.1.4 Tires & Wheels requirements.
T3 Touring 3 BOP adjustments for 2022 #31481weight +75 lbs
T3 BMW 330i Minimum Comp Weight #31606tyres & wheels -60 lbsfasterT3 BMW 330i/Ci 01-06 loses 60 lbs to 3125 and runs 245 tyres instead of 275.
T3 Adjust T3 370Z #31748weight +50 lbsslowerT3 Nissan 370Z 09-16 and 370Z NISMO 09-13 weight increased to 3375 lbs.
T3 TIR changes for FWD T3 models #31825inductionfasterT3 FWD models standardized to 36mm turbo inlet restrictor; Focus ST brakes enlarged, final drive changed to 4.06 (1-4) 2.95 (5-6); GTI 14.5-17 gear ratios revised DSG/STD.
T3 Reply to letter #31486/29879 T2-T4 Grill openings #31935aerofasterT2-T4 grill openings may remove non-metallic webbed false sections; 16 square inch limit removed.
T3 BRZ vs BRZ TS #32022wordingneutralT3 Spec Lines Subaru BRZ TS (13-21) added to class specification wording.
T3 Remove StopTech 4 piston BBK, allow any 4 Piston Kit - VW GTI #33082suspension & brakesneutralT3 VW GTI/Jetta GLI allows any 4-piston brake kit instead of StopTech only, max 355mm x 32mm.
EP Throttle Body and Idle Air #31800wordingneutralEP, FP, HP classes allow stock/original idle control devices unmodified or completely removed with openings blocked.
EP Porsche 968 Engine Questions #31831otherneutralEP Porsche 968 (92-95) now allows dry sump.
EP Request weight reduction for 1979-1985 Mazda RX-7 #31833weightfasterEP 1979-1985 Mazda RX-7 12A and 13B weight reduced by 50-53 lbs across all configurations.
GT2 GT2/ST Porsche Cayman #31451 correct TBR size error #31991enginefasterGT2 Porsche Cayman 05-15 turbo restrictor increases from 70mm to 75mm.
STU Request Allowance for Balance Shaft Delete in STU #31434enginefasterSTU engines may delete balance shafts and plug openings; alternate pulleys allowed for timing belt or chain operation only.
STU Request Louvers in hood vents #31916aeroneutralSTU hood vents allowed to include louvers within 200 sq. inch area.
EP Porsche 968 Engine Questions #31478enginefasterEP Porsche 968 intake valve size increased from 37 to 39.0 mm.
EP PCS E. 2. n. 4. Add Axle Shaft to Allow FWD the Same Freedom #31592wordingneutralEP, FP, HP front-wheel-drive cars may alter body and suspension to install alternate transmission, transaxle, and axle shaft.
EP BMW Z3 2.5L Spec Line #31724wordingneutralEP BMW Z3 2.5L allows alternate throttle body from 92-95 325i with Turner adapter; head casting 1738400 permitted with specific blocks.
GT2 Restrictor Clarification for 2015 Cayman #31451wordingunclearGT2 Porsche Cayman 05-15 uses Throttle Body Restrictor instead of Flat Plate Restrictor at 2700 lbs.
STU Request to Add Honda K23 Spec Line #30682cars addedneutralSTU adds Honda K23 with 2354cc displacement and minimum weight per chart, K24 block allowed with K23 internals and head.
STU RE: Aug FT letter 30682 #31060enginefasterSTU Honda K23 internals rule relaxed to require only K23 crankshaft, allowing other internal modifications.
STU Throttling Device Clarification #31323wordingneutralSTL and STU piston engines clarified: intake manifold and cylinder head porting remains free.
T3 Request FRS/BRZ/86 T3 Weight Reduction #30818weight -75 lbsfasterT3 Scion FR-S/Toyota 86 GT and Subaru BRZ lose 75 lbs, to 2675 lbs minimum weight.
T3 Request to Classify 2022 Toyota 86 / Subaru in T3 & T4 #30931cars addedneutral2022+ Subaru BRZ and Toyota 86 newly classified in T3 at 2750 lbs with 245 max tires.
T3 Reply to letter 29879 T2-T4 Grill Openings #31486aerofasterT2-T4 clarified: grill opening area may increase max 16 sq in for radiator cooling only, retaining factory mesh shape.
T3 Please Adjust Years Allowed for BMW 335i to 07-10, not 08-13 #31530wordingneutralT3 BMW 335i eligible model years narrowed from 08-13 to 07-10.
T3 Please Adjust Years Allowed for BMW 135i to 08-10, not 08-13 #31531wordingneutralT3 BMW 135i model years restricted from 08-13 to 08-10.
T3 Request to clarify radiator hoses #31682wordingneutralT2, T3, T4 radiator and coolant hoses may be replaced with aftermarket options; coolant temp sensor modification permitted.
T3 T3 Nissan Z Suspension Update #31728wordingneutralT3 Nissan Z 350Z and 370Z suspension control arm options expanded from 'and' to 'or' for SPC parts.
T3 Clarify Permitted/Allowed #31743wordingneutralT2, T3, T4 clarify that spec lines listing permitted or allowed parts are alternatives to category rules, not replacements.
EP 944S2 Restrictor #31396inductionslowerEP Porsche 944S2 89-91 requires 56mm flat plate intake restrictor; comp ratio max 12.0:1, valve lift max 0.500".
EP Classing Clarification for 1986 Toyota Corolla FX16 #31527cars addedneutralHP Corolla GTS RWD (84-87) added at 2300 lbs; HP Corolla FX16 FWD (87-88) added at 2260 lbs; old Corolla (84-87) removed.
T3 Request to correct model years BMW Z4 M Coupe #31371wordingneutralT3 BMW Z4 M Coupe model years corrected from 2007 to 06-08.
T3 Correct letter the 31327 #31563weight +150 lbsslowerT3 Subaru STI 15-20 weight increases 150 lbs, to 3350.
T3 Request to Classify 2014 VW Jetta 1.8t TSI #30436cars addedneutralT4 Volkswagen Passat, Jetta 1.8T adds 2014 model year to eligible years.
T3 Request Weight Reduction 323is #30765weight -100 lbsfasterT3 BMW 323Ci/Is 98-00 minimum weight reduced from 3100 to 3000 lbs.
T3 Class Newer STI in T3 #31327cars addedneutralSubaru STI (15-20) newly classified in T3 at 3200 lbs minimum weight with 37mm turbo inlet restrictor required.
EP E&O; MR2 Track #31120wordingneutralHP Toyota MR-2 1.6L (85-89) track corrected to 15.47 inches front and rear.
GT2 Turbo Request for 13B Engine #30656engineunclearGT2 Mazda 13B street port adds EFR 70/76 turbo with 42mm restrictor at 2280 lbs.
GT2 Request car classification #31032cars addedneutralGT3 Fun Cup Beetle EVO3 classified with 1984 cc sealed SOHC engine, 2060 lbs minimum weight.
GT2 Correct letter 30565 GT2/ST #31088weightfasterGT2 Dodge Viper Comp Coupe ACR/ACR-X loses 100 lbs minimum weight to 3275.
EP Request to Allow F22c Engine for 2000-2003 Honda S2000 #30548cars addedunclearHonda S2000 (00-03) reclassified as EP Prep with F22c engine option: 1997cc or 2157cc, weight 2450–2636 lbs depending on displacement.
EP Request a review of the S14 240SX in EP. #30873weight -200 lbsfasterEP Nissan 240-SX S13/S14 loses 200-210 lbs minimum weight; comp ratio rises to 12.0:1, valve lift to .500.
GT2 Request the 04-06 Pontiac GTO WC Car Be Added to the GT2/ST Chart #30339cars addedneutral04-06 World Challenge Pontiac GTO added to GT2-ST: 6062 cc, 3000 lbs minimum, unrestricted.
GT2 Request to Update GTA Obsolete Part Numbers #30615wordingneutralGTA part numbers updated: 0-80541-1 to 0-80541-2 in two sections and 6010 to 6014X in TA2 Appendix.
GT2 GTX class correction to GT2/ST #30973cars addedneutralGrullon GT with 2.0L K20 moved from GTX to GT2-ST, minimum weight 2350 lbs, unrestricted.
EP Lotus/Caterham 7 America Request #30392wordingunclearEP Lotus/Caterham 7 America carburetor changed from IT fuel injection prep to fuel injection.
EP Reclassify Daimler SP 250 #30721cars addedneutralDaimler SP 250 classified in EP at 2165 lbs with 2548 cc OHV 8-cylinder engine.
GT2 Porsche Cayman Engine Modification and Engine Request #30472inductionfasterGT2-ST Porsche Cayman restrictor increases from 65mm to 75mm flat plate at 2700 lbs.
GT2 Request weight clarification Viper CC #30565weightfasterGT2 Dodge Viper including Comp Coupe, ACR/ACR-X minimum weight reduced 100 lbs to 3275 in VRL Spec.
GT2 Variance, 2021 TA2 Rules vs GCR Appendix L #30641wordingneutralTA2 minimum weight set to 2930 lbs with free tire make and size.
STU STU Fender flares #30696wordingneutralSTU fender flare wording clarified: exterior contour of any wheel opening may not change opening size, location or shape from side view.
STU Request weight reduction for 12A bridgeport motor in Miata #30751weight -200 lbsfasterSTU Mazda 12A Bridge Port Miata weight reduced from 2550 lbs to 2350 lbs.
T3 Follow-up to letter 29797-Porsche Spec Boxster in T3 Adjustment #30144weight -50 lbsfasterT3 Porsche Spec Boxster minimum weight reduced from 2600 to 2550 lbs.
T3 Wheel Size #30677tyres & wheelsfasterT3 Porsche Cayman 06-08 wheel size changes from 18x8 to 18x9 inches.
T3 Request weight adder to be applied to the Global Cup Miata ND2 #30730weightslowerT3 Mazda MX-5 Global Cup Miata ND2 with sequential gearbox allowed +100 lbs weight adder.
EP Clarify Application of Percentage Based Weight Penalties #30669weightslowerEP, FP, HP clarifies percentage weight penalties sum first, then apply to base weight, rounding to nearest pound.
T3 Civic Type R Brake Rotors #29817weightslowerT3 Honda Civic Type-R 2020+ allows brake rotor 45251-TGH-A01 with 25 lb penalty.
EP Change Classification of 84-87 Mazda 626 from FP to HP #30350cars addedneutral84-87 Mazda 626 reclassified from FP to HP with 2300–2415 lbs weight, 1998cc SOHC, dual 32mm carbs.
EP Fiat X1/9 brake rotors #30423suspension & brakesneutralFP Fiat X1/9 brake rotors change to 257 (10.1) x 12 (.407) solid disc.
EP NC MX-5 year range correction E&O #30503wordingneutralEP Mazda MX-5 year range corrected from 06-14 to 06-15.
STU Request for Fender Flare Clarification #30375wordingneutralSTU fender flare rules clarified: maximum 2 inches, must cover tire contact patch from above, cannot alter body configuration or wheel opening geometry.
T3 Requesting Variance on Hardtop #30093wordingneutralT3 Porsche Boxster/Boxster S (00-04) now permits any OEM or aftermarket hardtop retaining OEM roof silhouette.
T3 07-09 and 10-13 Mazdaspeed 3 Fuel Pump #30154wordingneutralT3 Mazdaspeed3 07-09 and 10-13 now allow CorkSport Gen-6-999-10 or Autotech 10-127-100K fuel pumps.
EP Please Classify Mazda3 in FP #30165cars addedneutralMazda 3 S 04-08 classified in EP at 2350 lbs minimum, 2.26L DOHC, 12.0:1 compression, .500" valve lift limit.
GT2 GT2 tiger firing order #30421wordingneutralGT2 Sunbeam SBF 302 engine firing order option now explicitly allows Boss 302 variant.
STU Provision for Interchangeable Engine Components Already Allowed #30342engineunclearSTU Honda S2000 allows F20/F22 K24 crankshaft with chart weight for achieved displacement.
STU ST Oil Coolers E&O Correction to 9.1.4.2.H #30388wordingneutralST oil coolers and filters now explicitly allowed to be added or substituted; wording clarifies existing permissions.
T3 Request consistency review in GCR #30263wordingslowerT2-T4 clutch disc and pressure plate must be at least 95% of factory OEM weight.
T3 Request to classify 2006-2008 Cayman #30315cars addedneutralPorsche Cayman 06-08 classified in T3 with 2687cc engine, 3050 lbs minimum weight, 18-inch wheels, 245 tires.
GT2 GT2-ST CORVETTE CHANGES #30029weight +100 lbsslowerGT2-ST Corvette (-2019) LS2 and L76 5967cc gain 100 lbs minimum weight to 3100; 6162cc variants gain 50–100 lbs; 7011 gains 100–50 lbs; L76 restrictor opens 70 to 73 mm.
GT2 29742 Change new wording to read as: #30329wordingneutralGT2 Ford Mustang/Thunderbird Boss 302 firing order now optional from later SBF 302 versions.
STU Super Touring Alternate Miata Hubs #30345wordingneutralSTL/STU 90-05 Mazda Miata gains approval for Mazda Motorsports Development alternate front wheel hubs.
T3 2020 T3 Suggested Changes #30002wording -50 lbsslowerT3 Ford Mustang EcoBoost gets 35mm TIR; Nissan 350Z DE Motor down 25 lbs to 3250; Mustang V6 down 50 lbs to 3475, restrictor tightened 55mm to 58mm.
GT2 ABS Restrictions #30064wordingneutralGT2 ABS braking systems now allowed if shown on individual Spec Line.
STU Brake Component Relocation #29990wordingneutralST cars may relocate ABS actuation hardware and wiring anywhere in engine compartment.
STU Porsche PDK #30081wordingneutralSTU Porsche PDK automatic transmission limited to 8 forward speeds instead of torque converter restriction.
STU Reference Letter #29333 Proposed STU 13B Spec Line Changes #30086inductionfasterSTU Mazda 13B Street Port 2400 removes choke location restriction, allows auto-type 2bbl with dual-Y manifold.
STU Drive Shaft Request #30087wordingneutralSTU driveshaft and half-shaft materials change from OEM-type to steel or aluminum.
T3 2021 Toyota Supra #29567cars addedneutralToyota Supra 2020- newly classified in T2 at 3450 lbs minimum weight with 295 tire and 19-inch wheels.
T3 Chevrolet Camaro LT-I4 Turbo 1LE (2019-) Model Year to 2016- #30090tyres & wheelsfasterT3 Chevrolet Camaro LT-I4 Turbo 1LE reclassified to 2016- model year, max tire size 275, TIR required 35mm.
T3 Fix T2 Mustang spec line #30106wordingneutralT2 Ford Mustang GT 5.0L (15-17) gear ratios corrected to 3.66, 2.43, 1.69, 1.32, 1.00, 0.65 or 4.17, 2.34, 1.52, 1.14, 0.87, 0.69.
T3 Spec Boxster Tire Size #30159tyres & wheelsfasterT3 Spec Boxster tire size increased from 225 to 245 DOT, permitting wider tires.
EP Alternate Front Brake Rotors and Calipers for EP AH 3000 #29893suspension & brakesneutralEP Austin-Healey 3000 Mk. I, II, III now allows TR-6 front calipers and discs as alternate.
GT2 Request change to engine firing order rule #29742engineunclearGT2 Ford Mustang/Thunderbird Boss 302 firing order becomes unrestricted.
GT2 Request E-46 BMW M3 balance of performance #29833weight -100 lbsfasterGT2 BMW E46 M3 weight reduced from 2600 to 2500 lbs.
STU 13B Rules Adjustment #29333cars addedslowerSTU Mazda 13B Street Port classified at 2400 lbs minimum weight, replacing peripheral and bridge port variants.
T3 Request to Classify BMW M2 CS #29523cars addedneutralBMW M2 CS Cup 2020+ classified in T2 at 3625 lbs with 2979cc engine, 10.5x18 wheels, 295 tires.
T3 Allow the SpecMX-5 Update Kit Into Touring 4 for the MX-5 #29681wordingunclearT3 and T4 Mazda MX-5 06-15 now allow Mazda Transmission kit part # 0000-02-5700.
T3 350Z Rear Caliper Replacement #29710wordingneutralT2 and T3 Nissan 350Z and 370Z permit 44011-RC350 rear caliper kit and SZ350 rotors.
T3 Request Mustang 8.8†rear axle replacement #29860weightslowerT4 Ford Mustang V6 05-10 allows GT 8.8 rear axle with 3.55 final drive, adds 25 lb penalty.
T3 Cap year range on all 86s #29908wordingneutralT3 and T4 FR-S, 86, and BRZ year ranges capped: T3 at 2021, T4 at 2017-2021.
EP Mk2 VW Consistency and Cleanup of FP and HP Spec Lines #29195weight -50 lbsfasterFP Volkswagen Golf and Jetta 1.8 lose 50 lbs each, to 1900. HP Jetta GLI engine code removed.
EP Correct Wording for Level 1 and Level 2 Induction Systems #29406wordingneutralEP, FP, HP Level 1 and Level 2 induction systems: clarified carburetor and fuel injection rules, jets/needles/rods unrestricted in Level 2.
EP Weight Reduction for Datsun Roadster #29409weight -75 lbsfasterEP Datsun SRL 311U Roadster minimum weight reduced to 1925 lbs from 2000 lbs.
EP EP TR8 Adjustment #29512weight -100 lbsfasterEP Triumph TR8 78-81 weight reduced from 2600 to 2500 lbs.
GT2 Request for Bigger Engine in Plymouth Breeze #29380cars addedneutralGT2 Chrysler/Dodge/Plymouth 2429cc DOHC engine classified at 1950 lbs, unrestricted fuel induction.
STU Request clarification on wing measurement #29640aeroneutralST aero devices and reference areas now include end plates but exclude fasteners protruding over 1/2 inch.
T3 Alfa Romeo 4C Launch Edition #29531wordingneutralT3 Alfa Romeo 4C Launch Edition now allowed in Spec Lines.
EP 84-87 Toyota Corolla HP Wheel Diameter Allowance Proposal E&O #29458tyres & wheelsfasterHP 84-87 Toyota Corolla wheel diameter increases from 13 to 15 inches.
GT2 rescind GT2 stock car bodies removal #29219cars addedfasterGT2 stock car bodies removal rescinded; 1997-current year commercially available stock car bodies remain allowed.
GT2 E&O Typos in Appendix L #29447wordingneutralGT2 Appendix L renumbering eliminates sections .17 through .19 after 4.8.4.2.10.3.6.
GT2 GT2 wing width wording correction #29469wordingneutralGT2 TA2 wing width maximum set to 65 -5/16 inches, previously undefined.
T3 Request to Classify Honda Civic Type R in T3 #27840cars addedneutralHonda Civic Type R (2017-) classified in T3 at 3350 lbs with 1996cc engine, 245 max tire, 20-inch max wheel.
GT2 GT Category Wording #29193wordingunclearGT1, GT2, GT3, GTL, GTX now permit turbocharging/supercharging if listed on spec line.
GT2 Corvette GT2-ST intake manifold #29221wordingneutralGT2 Chevrolet Corvette -2019 LS1/LS6 allows DORMAN part # 615-900 alternate intake manifold.
GT2 997.2 E&O link to 27915 #29373weightfasterGT2 Porsche 997.2 GT3 Cup minimum weight drops to 2900 lbs.
STU Request for Advanced Aero Rule Wording Clarification. #29124wordingneutralSTU fender flare rules reworded: up to 2" per corner allowed with 1% weight penalty total.
EP EP BMW Z3 Rule Clarification #28998wordingneutralEP BMW Z3 2.5L iron block casting 1738566-C designation removed, wording clarification only.
GT2 Request for allowance Trans Am SGT #28951wordingneutralGT2 BMW E46 M3, E36, Z3, and 5000cc V8 gain Trans Am SGT spec allowance: regular shifter 3000 lbs., paddle shifter plus 150 lbs.
GT2 Omitted GT2 fender/hood openings #29171aeroneutralGT2 allows up to four hood/fender louvered panels, max 600 sq inches total, min five slots each, mounted in front of windscreen.
STU Minimum Weight Determination #27695wordingneutralSTL and STU clarify weight adjustment calculation order: engine adjustments first, then chassis adjustments.
STU ST Gurney flap Wicker clarification #29012wordingneutralSTL and STU rear wing rules clarify that wicker is a Gurney flap; no performance change.
T3 Request to classify 2009 Honda Accord v6 manual #28913cars addedneutralT3 Honda Accord (2009) V6 manual classified: 3471cc, 3450 lbs, 245 max tire, 19-inch wheels.
EP Request to Classify Porsche 911 2.0L #28456cars addedneutralPorsche 911 S 67-68 classified in EP at three weight levels: 1800, 1845, or 1890 lbs.
GT2 TA2 Gurney flap wicker clarification #28874wordingneutralTA2 Gurney flap wording clarified: terminology standardized to 'Gurney flap', height limits and thickness specifications remain 0.50 inch / 0.625 inch or 0.375 inch / 0.0625 inch depending on configuration.
GT2 STO Gurney flap wicker clarification #28883wordingneutralSTO rear wing wording clarified: 'wicker' changed to 'Gurney flap' in maximum chord and mounting height rules.
STU Request for Alternate Intake Manifold #26514wordingneutralSTU request for alternate intake manifold denied; no rule change issued.
STU Request for Addition to GT3 Approved Turbo List #27576wordingneutralGT3 and STU add Borg-Warner EFR6258 to approved turbocharger list.
STU Request BoP for my Car #29004wordingneutralSTU large displacement turbo engines limited by GCR turbo list; non-turbo trim suggested as more competitive.
STU Sequential Shifters in STU #29031wordingneutralSTU sequential shifters referred to Board of Directors for approval; no change implemented yet.
T3 SADEV Sequential Gearbox #28763wordingneutralT3 Mazda MX-5 Global Cup Miata ND2 2016-2019 must meet all ND2 Global Cup rules without appendix reference.
T3 Request for competition adjustment for the MK5 GTI FSI engine #28802suspension & brakesfasterT3 VW GTI FSI gains turbo inlet restrictor allowance to 60mm, R32 brakes, Stoptech 4-piston kit, and Neuspeed intake options.
T3 Request to Add a Vehicle to the Roster (contd.) #27698cars addedunclearCannot read: letter references external document #27663 not provided.
EP BMW Cylinder Head Casting and Part Numbers #28708engineslowerEP BMW 2.8L, 328i E36/E46, and 325i E36 blocks now iron only; 325i E46 aluminum only.
GT2 Request to Adjust Weight of OEM 8.4 Viper #28739weight -50 lbsfasterGT2 Dodge Viper 8400 OEM minimum weight drops 50 lbs to 3275.
GT2 Request to Adjust Weight of OEM Chevrolet Corvette #28896weight -50 lbsfasterGT2 Chevrolet Corvette -2019 OEM minimum weight cut 50 lbs to 3275.
STU Rotary Help #27833cars addedneutralSTU Mazda 13B Bridge Port and Street Port engines added with 2550 and 2250 lbs minimum weights respectively.
T3 Request to Classify 2004 Mercedes Benz 320 CLK #27663cars addedneutral2004 Mercedes Benz CLK 320 Coupe classified in T4 at 3200 lbs with 3299cc engine and Eibach PN# 2563.140 springs allowed.
T3 Request Nissan 350Z Part Number change #28145enginefasterT3 Nissan 350Z Spec 2 DE Engine loses 57mm flat plate restrictor requirement.
EP Request to Classify 1990-1994 Mazda Protege #28381cars addedneutral1990-1994 Mazda Protege classified in FP Pre at 2150–2258 lbs with 1839cc DOHC engine, fuel injection.
EP Error in Mini Cooper Spec Line #28713wordingneutralHP Mini Cooper model year ranges for convertibles revised: 02-06 now includes 05-08, 07-13 now includes 09-15.
GT2 Request Corvette engine parity #28576weightfasterGT2 Corvette LS6 may reduce weight by 50 lbs.
T3 2015 + Ford EcoBoost Mustang Sway Bars #28398suspension & brakesneutralT3 Ford Mustang EcoBoost and V6 sway bars allowed up to 35mm front, 25mm rear.
T3 Z3M Roadster Weight #28437weightfasterT3 BMW Z3 M & Coupe 1998-1999 weight reduced from 3350 to 3150 lbs.
EP Caterham 7 Spec Line #28498wordingneutralEP Caterham 7 Spec Line removes redundant suspension note, clarifies engine prep limits and comp ratio to 10.0:1.
GT2 Request to revisit Panoz GT-S BoP #28280wordingunclearGT2 Panoz GT-S now allowed to use TA2 Choice Engine with any 5-speed H-pattern transmission.
GT2 GT2-ST Corvette LS2 & L76 #28583inductionfasterGT2-ST Corvette LS2 restrictor increases from 70mm to 75mm flat plate.
STU Request to approve Honda S2000 HKS supercharger #27281enginefasterSTU Honda S2000 adds HKS Supercharger kits 12001-AH006 and 12001-AH010 as allowed.
STU Request BoP on the Lotus #27637weight +100 lbsslowerSTU Lotus Elise Cup R and SC models, plus Exige SC, gain 100–200 lbs minimum weight.
STU Turbo Inlet Restrictor On MK5 Volkswagen #27704inductionslowerSTU Volkswagen GTI/GLI MK5 and Jetta Mk4 may install turbo inlet restrictor in OEM turbo inlet housing.
STU Honda K20C1 removal #27732inductionslowerSTU Honda K20C1 Turbo I4 restrictor reduces from 36mm to 35mm.
STU Change GM LNF 2.0 Allowance to LSJ Engine for Viable STL 2.0 #27884engineslowerSTU GM Ecotech LNF now allowed with turbo removed or with LE5 head and intake manifold, meeting STL specs.
STU Alternate Engine for Porsche 944 #28259engineunclearSTU Porsche 944 now permits VW/Audi 1.8L and 2.0L turbo engines as alternates.
EP Request to Review Horsepower Parity #27662engineslowerEP BMW Z3 2.5L compression ratio capped 12.0:1, valve lift .500, 59mm restrictor required; Z3 2.8L same limits added; 944S2 compression 12.0:1, valve lift .500, 56mm restrictor required.
EP E36 (92-95) Brakes Errors and Omissions #28058weightfasterEP BMW 325is M-Technic loses 100–105 lbs across three weight configurations, to 2550–2678.
EP Request to allow 40 DCOE carb for the Datsun 510 #28195inductionfasterHP Datsun 510 gains 40 DCOE carburetor option alongside existing 40 DCN and 36mm DCNVH choices.
EP Add Throttle Body Size these EP BMW Spec Lines #28422inductionslowerEP BMW fuel injected throttle body maximum inside diameter set to 64mm.
GT2 Request 991.2 Porsche engine displacement verify typo #28194enginefasterGT2 Porsche 991.2 GT3 Cup Car engine displacement increases from 3.8L to 4.0L.
STU Please Modify the STU Wheel Size Rule for Clarity #27694weightfasterSTU vehicles over 2951 lbs base weight may use 9 inch wide wheels, up from 2950 lbs.
STU Turbo Engine Cars Base Weight #28032wordingneutralSTU turbocharged engines now use base weight instead of minimum weight, with 3% DI increase applied to base weight.
T3 Clarify 05-10 V8 Mustang Spring Rates Wording/Adjust Restrictor #28238wordingneutralT3 05-10 V8 Mustang allowed parts clarified: strut tower brace, radiator, springs to 500 lbs/in front and 300 lbs/in rear, sway bars, damper kit.
T3 Correct Touring 3 05-10 Mustang final drive #28288wordingneutralT3 Ford Mustang Coupe GT & Shelby GT 4.6L 05-10 adds permitted final drive ratios: 3.31, 3.55 or 3.73.
EP Request for Help for Datsun 1200 #27934inductionfasterHP Datsun 1200 carburetor choke size increases from 26mm to 30mm.
GT2 Windshield Clips #27323wordingneutralGT1, GT2, GT3, GTL, GTX may omit windshield clips if factory glass is bonded per original specifications.
GT2 Request to Add Chevrolet SS Body to Appendix L #27898cars addedneutralGT2 Chevrolet SS replaces Dodge Charger; all stock car bodies removed from GT2 in 2021.
T3 2006 BMW E90 330i Sedan Classification #26663cars addedneutralBMW 330i 2006-2012 added to T3 with 2996cc engine, 3200 lbs minimum weight.
T3 Please Switch the Solstice GXP as Specified in T2, to T3 #27413cars added -50 lbsfasterPontiac Solstice GXP and Saturn Sky move from T2 to T3; wheels widen to 18 x 9.5 inches, Sky weight drops to 3200 lbs.
T3 Request to Classify all Mazda RX8 Models in T3/T4 #27606cars addedneutralMazda RX-8 Base/R3/Sport/GT (04-12) classified in T3 effective 2020-02-01.
T3 Request for 2005 Subaru STI Changes #27658tyres & wheels +50 lbs
T3 Request to Classify 2017 Ford Fiesta ST #27700cars addedneutralT3 adds 2017 Ford Fiesta ST, 1596cc, 2600 lbs minimum weight, 245 max tire, 17x9 wheels.
EP Request to List Mazda Miata Throttle Body Size #27907wordingneutralFP and EP Mazda Miata models standardized to 55mm throttle body diameter; brake spec clarified.
GT2 Request Factory Five Daytona coupe classification #26308cars addedneutralFactory Five Type 65 Coupe R with Ford 302/351 or 5.0/5.2L NA added to GTX-MISC at 2600 lbs.
GT2 Porsche 991.2 GT3 Cup GT2 Classification #27701cars addedneutral991.2 GT3 Cup Car classified in GT2 at 3100 lbs with 63mm throttle body restrictor.
GT2 Request for Acura NSX Spec Line Changes #27755weightfasterGT2 Acura NSX minimum weight reduced from 3000 to 2700 lbs.
GT2 GT2 991.1 restrictor size change #27914inductionfasterGT2 Porsche 991.1 GT3 Cup restrictor size increases from 67 mm to 70 mm.
GT2 GT2 996/997.1 weight change #27915weight -100 lbsfasterGT2 Porsche 996/997.1 GT3 Cup minimum weight reduced 100 lbs, to 2800.
GT2 GT2/ST Corvette comp adjustment #27920inductionslowerGT2/ST Corvette -2019 5967cc restrictor reduced from 75 mm to 70 mm.
T3 Clarification of On-Board Fire System for T2 #27183wordingneutralT2 requires onboard fire system; T3 and T4 may have one per GCR 9.3.
T3 Mustang Ecoboost and GT Transmission #27439otherunclearT3 Ford Mustang EcoBoost 2015- gains three transmission gear ratio options.
T3 Nissan 350Z HR Engine Restrictor Plate/Minimum Weight #27442induction +50 lbsslowerT3 Nissan 350Z and 370Z HR engines: restrictor plate enlarged from 37mm to 42mm, weight increased 50-100 lbs.
T3 Request help for the GMX5 #27572tyres & wheelsneutralT3 Mazda MX-5 Global Cup Miata (2016-) tires now 215/610 R17 BF Goodrich G-Force Slick or wet; removes touring tire requirement.
T3 Request for 05-10 Mustang GT Suspension Upgrades #27777suspension & brakesfasterT3 05-10 Mustang GT 4.6L suspension upgrades allowed: tower braces, radiator, 500/300 lbs/in springs, sway bars, dampers, control arms, shocks, driveshaft.
T3 Please Update the BMW SpecE46 Rules #27781wordingneutralT3 BMW SpecE46 updates to SpecE46 rules Version 2.6 to 2.7, tire width to 225 maximum.
T3 Request for 02-03 WRX Spec Line Parts #27864weight -100 lbsfasterT3 Subaru WRX 02-05 minimum weight drops 100 lbs to 3250.
T3 T4 RX8 Classification Error #27902wordingneutralMazda RX-8 Base/R3 (04-12) reclassified in T3 and T4 to include Sport and GT variants.
T3 Request to add Toyota 86 GT to Spec Line #27910cars addedneutralToyota 86 GT (2017-) added to T3 and T4 Spec Line.
EP Re-organize Prep2 Cylinder Head Rules for Clarity & Consistency #27661wordingneutralEP, FP, HP cylinder head rules reorganized for clarity; no performance change.
STU Request for an electronic throttle body #27342wordingneutralSTU cars with manual OEM throttle bodies may convert to OEM electronic throttle body of same inner diameter.
T3 Request to add 2018 Subaru BRZ in T3 #27253cars addedneutralT3 Scion FR-S/Toyota 86 and Subaru BRZ year range extended from 13-17 to 13-20.
T3 Request Mazda NC MX-5 alternate transmission gear ratios #27155wordingneutralT3 Mazda NC MX-5 gains two alternate six-speed and one five-speed transmission gear ratio option.
EP Request bodywork for Austin Healey Bugeye Sprite MK1 #27106wordingneutralFP and HP Austin-Healey Sprite Mk I and MG Midget variants may replace rear bodywork aft of cockpit with stock-appearing alternate material components.
EP Request to classify the GMX5 2019 #27263wordingneutralEP Mazda MX-5 Global Cup classification year changes from 16-18 to 16-19.
EP level one susp. component rule #27270wordingneutralProduction suspension rule clarifies spindles, hubs, bushings, bearings, ball joints unrestricted.
EP Clarification of Carb Rules - Prep 1 #27300wordingneutralProduction carb rules clarified: carburetor options, fuel injection throttle body dimensions, and intake manifold restrictions reorganised and refined.
EP Clarification of Carb Rules - Prep 2 #27301wordingneutralEP, FP, HP carburetors clarified: jets, needles, metering rods, needle valves unrestricted; choke parts removable; permitted optional carburetors listed.
STU Request to correct E&O advanced aerodynamics #27290wordingneutralSTU wing assembly wording corrected: no part higher than roof height.
T3 Request spare tire/wheel clarification #27012wordingneutralT2-T4 spare tire/wheel rules clarified: removable covers can be removed with hardware and bracketry.
EP Request Miata Eligibility - 2003 #27121cars addedneutralEP Mazda MX-5/Miata eligibility years expanded from 1999-2002 to 1999-2005.
T3 Request guidance for 2014-2017 MK7 Volkswagen GTI #26866wordingneutralT3 Mk7 GTI gains R32 brake package, 4-piston Stoptech kit to 355mm, and ECS street shield allowance.
GT2 TA2 Weight Clarification #27077weightslowerGT2 TA2 cars must weigh minimum 2930 lbs per current Trans Am rules or prior Appendix L.
STU Remove -2mm penalty from SR20DET Nissan #26982enginefasterSTU Nissan SR20DET removes -2mm penalty in Table B.
STU Request clarification for manifold and throttle in STU #27004inductionfasterSTU alternate intake manifolds now allowed case-by-case instead of prohibited.
T3 Request BMW e36 M3 sway bar and links #26885suspension & brakesneutralT3 BMW E36 M3 96-00 allows alternate sway bars, 35mm front and 27mm rear.
GT2 Request to classify Toyota Supra with 3SGTE engine #25185cars addedneutralGT2 Toyota Supra 3SGTE newly classified at 2900 lbs minimum weight, 43mm restrictor.
GT2 Request to Classify Acura NSX from T1 to GT2? #26121cars addedneutralAcura NSX All Years classified to GT2-ST: 3.5L turbo, 3000 lbs minimum, 43mm restrictor.
GT2 Request for TA2 BOP in GT2 #26509weightslowerGT2 TA2 minimum weight increases from 2830 to 2930 pounds.
STU Request to clarify afterrmarket side skirts exhaust exit #26814wordingneutralSTU aftermarket side skirts must meet 3-inch ride height, no openings except jacks or side exhaust, no wider than fascias, not higher than door bottom, no chassis reinforcement.
STU Wheel Flare wording #26872wordingneutralSTU fender flare wording clarified: each fender may be flared up to 2" for tire clearance with 1% weight penalty.
T3 Request to properly class base Porsche Cayman #26276cars addedneutral09-12 Porsche Cayman newly classified in T3 at 3150 lbs with 2900cc engine.
EP Allow Firewall Modification for Fitment of 13B into RX8 #26726wordingneutralEP Mazda RX-8 firewall modification allowed for 13B engine fitment in stock location.
GT2 Request for e36/e46 bmw 4500 cc v8 at 2950lbs in GT2/ST #26106cars addedneutralGT2 BMW E36/E46 4.5L V8 classified at 2950 lbs minimum weight.
GT2 Request GTX Fuel injection for previous GT-1 tube frame cars #26141inductionfasterGTX tube frame cars gain fuel injection with 90mm maximum throttle body size.
GT2 Request to Classify Ligier JS2 R #26535cars addedneutralLigier JS2 R classified in GTX, no performance parameters specified in filing.
STU Request Ride Height Clarification #26597wordingneutralSTL and STU ride height measurement clarified: without driver, at rocker panel lowest point, excluding pinch weld.
T3 Request to classify a 2019 Chevrolet Camaro LT-I4 Turbo 1LE #25731cars addedneutralT3 Chevrolet Camaro LT-I4 Turbo 1LE (2019-) classified with 1998 cc engine, 3450 lbs minimum weight, 245 max tire size.
T3 T3 Civic Si weight change #26294weightfasterT3 Honda Civic Si 2017- minimum weight reduced 100 lbs, to 2900.
T3 Class Civic Si 2017+ w/ alternate cage #26449cars addedneutralHonda Civic Si 2017+ with alternate cage classified in T3 at 3075 lbs minimum weight.
T3 Classify 2014-2017 MK7 Volkswagen GTI for T3 #26695cars addedneutralT3 classifies 2014-2017 Volkswagen GTI with 35 mm turbo inlet restrictor, 3080 lbs DSG, 3050 lbs standard.
EP Rollcenter Correction Clarification #25873suspension & brakesfasterEP, FP, HP clarified: tapered holes in ball joints now allowed for bolt conversion; wheel bearings and hubs unrestricted at any wheel.
EP Hardtops #26476wordingneutralEP open cars may now use aftermarket hardtops if they retain OEM appearance; specific model hardtop allowances removed.
GT2 Request Ford Perfomance 5.2L crate engine FPR clarification #26159cars addedneutralGT2 Ford Mustang 5.2L classified at 3300 lbs minimum with 82mm single throttle body restrictor.
GT2 Request Ride Height Clarification #26600wordingneutralGT1 and GT2/GT3/LITE ride height requirements removed from GCR sections 9.1.2.D.5.a.1 and 9.1.2.F.7.b.
STU Request to Use Japanese Mazda 13b Intake Manifold #25790inductionfasterSTU Mazda 13B Bridge Port may use ELITE ROTARY SHOP FD V2.0 intake manifold instead of stock.
STU Request Alternate Intake for Mazda MZR In a Rear Wheel Drive App. #26352inductionunclearSTU Mazda MZR LF/L3/L5 may use Goodwin Part #61-2510 intake manifold with stock or Acura throttle body.
STU E&O Suspension #26424wordingneutralSTU suspension rules clarified: alternate components from same manufacturer moved from section E to section D.
STU Revisit B20 VTEC #26530enginefasterSTU Honda/Acura B20 classified at 1973 cc, now permits VTEC B16 or B18 cylinder head and intake manifold.
STU Move Flared Fenders to STU Advanced Aero #26564aeroneutralSTU flared fenders up to 2" with 1% weight penalty moved from base to Advanced Aero rules.
STU TCA Civic SI E&O #26606tyres & wheelsslowerTCA Honda Civic Si (2017-) must run 37mm TIR maximum as of June 1, 2019.
STU S54 Spec line #26620wordingneutralSTU BMW S54B32 OEM reclassified from E46 designation, 3246 cc, 3300 lbs minimum weight.
T3 Request to allow E36 M3 in T3 prepared to BMWCCA I sport #25195cars addedneutralBMW E36 M3 (96-00) BMWCCA I Sport newly classified in T3 at 3100 lbs minimum weight.
EP Request for Competition Adjustment for 2nd Generation RX7 #25935weight -50 lbsfasterEP Mazda RX-7 12A and 13B (79-85) lose up to 80 lbs; 13B (86-91) loses up to 79 lbs.
GT2 Request Porsche Cayman year classification #26241wordingneutralGT2 Porsche Cayman model years change from 05-11 to 05-15.
STU Request to Class Assignment for 2017 Civic #24287cars addedneutralHonda Civic Si 2017- classified STU at 1500cc, 2800 lbs minimum with OEM engine and bodywork.
STU Request to run E46 3246cc in STU #25126cars addedneutralSTU BMW E46 S54 OEM 3246cc added at 3300 lbs minimum weight, no Super Touring allowances.
STU Engine Classification for Rotary #25564wordingunclearSTU Mazda 13B and 13B Bridge Port may use RE or REW housings and intake with turbo removed.
STU K24/K20 Head Swap Clarification/Amendment #25899wordingneutralSTU Honda K24 may use intake part #s 17100-RRB-A00 or 17100-PRB-A10.
STU Request to Classify 12a Bridge Ported Rotary Engine #25985cars addedneutralSTU Mazda 12A Bridge Port engine classified at 2550 lbs minimum weight with specified carburetor induction options.
STU World Challenge Car Eligibility #26387wordingunclearSTU World Challenge car weight calculation method removed; new basis unclear from text provided.
STU Request a phone call for discussion regarding weight #26398inductionfasterSTU AWD cars no longer required to reduce restrictor 1 mm from table.
STU Advanced Aero E&O #26413aeroneutralSTU rear wing maximum cord length set to 12 inches, end plates to 72.0 square inches each.
T3 Request Mustang GT Limited Prep 2018 Classification #24431cars addedneutralT1-LP Ford Mustang GT 5.0L 2018+ classified at 3400 lbs with 65mm flat plate restrictor.
T3 Classify 2015+ WRX #25832cars addedneutralT3 Subaru WRX (2015-) classified at 3275 lbs with 35mm turbo inlet restrictor required.
T3 Correct Mazda MX-5 Hard Top Notes #26137wordingneutralT4 Mazda MX-5 Club (06-15) and (2016-), T3 MX-5 Cup and Miata (2016-) hardtop rules clarified; wording changes to permitted parts and specifications.
T3 Request to allow T3 06-15 Miata 17x8 wheels #26161tyres & wheelsfasterT3 Mazda MX-5 NC 06-15 wheel width increases from 17x7 to 17x8.
T3 Request T3 06-15 Miata header #26162aerofasterT3 Mazda MX-5 NC 06-15 now allows any aftermarket header.
T3 Request Pontiac GXP same allowances to Saturn Sky #26175aerofasterT3 Saturn Sky intercooler tolerance increases from 32mm to 35mm TIR; new calipers and springs permitted.
T3 Consider opening class rules to allow any thermostat #26187wordingneutralT2, T3, T4 now allow any thermostat serving only OE intent, previously restricted.
T3 2005-2009 Legacy GT/Spec B #26384cars addedneutralT3 Subaru Legacy GT/Spec B 05-09 newly classified with 2457cc, 18×9 wheels, 245 tires, 3300 lbs.
T3 Cap 2016 Mazda Miata year at 2018 #26388wordingneutralT3 and T4 Mazda MX-5 Miata eligibility capped at 2018 model year, effective 2019-03-01.
T3 Request correction on brake sizes #26170wordingneutralT3 Mazda Mazdaspeed3 07-09 front brake disc increases to 320mm vented, rear to 300mm solid.
GT2 ST/GT2 BMW Flossman Kit Clarification #22138wordingunclearGT2 BMW E46 M3, E36, Z3, and 5000cc V8 now permit Flossman body kit.
GT2 Request Clarification/Revision of Appendix L (2013 TA2 Rules) #25110otherfasterGT2 TA2 cars: wheels cost cap drops to $175 each, carbon fiber allowed on rear wing, engine setback maximum 21.75 inches (A-F) or 24 inches (G), various nomenclature and clarification updates.
GT2 Request to classify BMW E82 (1 series) into GT2 #25539cars addedneutralBMW 1 Series E82 classified into GT2 with N52B30 engine, 2996 cc, 2140 lbs minimum weight.
GT2 2010 Cayman Street Tuner Into an STO Car,Addendum #25545weightfasterGT2 Porsche Cayman 05-11 base weight drops 75 lbs to 2800; adds STO/X51 motor notes.
GT2 Request - Classify Ford Performance 5.2l #25716cars addedneutralGT2 Ford Mustang 05- with 5.2L Aluminator engine classified: 3400 lbs minimum weight, 2×41mm flat plate restrictor.
GT2 Add missing displacement, minimum weight. Remove #25765wordingneutralGT2 Porsche 996/997.1 GT3 Cup adds 3.6L displacement and 2900 lbs minimum weight; removes aftermarket exhaust header allowance for 996.
GT2 Request for Ford FP 350s Weight Reduction #25806weightfasterGT2 Ford Mustang FP350S minimum weight reduced 100 lbs, to 3400.
GT2 Request to Classify EcoBoost Mustang #25842cars addedneutralGT2 Ford Mustang 05- EcoBoost classified: 3500cc, 3200 lbs minimum, 41mm restrictor.
GT2 Request to Remove Mazda RX 7 Body Work Penalty #26024weightfasterGT2 Mazda RX7 Downing GTS body kit allowed without 75 lbs. weight penalty.
GT2 GTX Homologation table update #26034cars addedneutralGTX FIA GT3: Audi R8 40mm restrictor 2900 lbs, BMW Z4 70mm 2800 lbs, Ferrari 488 35mm restrictor 3025 lbs classified.
STU Request to Equalize Direct Injected Turbo Cars #24890cars addedneutralSTU Honda K20C1 Turbo I4 1996cc added at 3025 lbs minimum weight with 36mm TIR.
T3 Errors, Omissions, and Updates (Various) #22414wordingneutralT4 Ford Fiesta ST years corrected to 14-; T4 Fiat 124/Abarth Edition years added 16-18; battery rule clarified.
T3 Request to update SpecE46 Appendix N. with 2019 Rules #25722wordingneutralT3 BMW SpecE46 rules reference updated from Appendix N to Version 2.6 Effective Jan 1, 2019.
T3 Request Alternative Nissan Brake Parts - 350Z #25747suspension & brakesneutralT3 Nissan 350Z Track/Touring/Standard/Nismo 03-08 permitted to use Nissan brake kit part number 41000-BRKIT.
T3 Add Clarification to Spec Car Classifications Vehicle Spec #25774wordingneutralT1-T3 spec cars receive clarifications on permitted modifications, documentation requirements, and rule conformance; no performance changes.
T3 Clarify Subframe Bushings Permitted for T2-T4 #25800wordingneutralT2-T4 subframe bushings may now be replaced with non-spherical bushings of any material.
T3 Additional weight adjustments for T3 cars T3 weight loss #25803weightfasterT3 field loses 50 lbs across 27 cars including Acura TL, BMW 335i, Camaro, Mustang, Miata, RX-8, 370Z, WRX.
T3 Request for Alternate EcoBoost Mustang Brakes #25813suspension & brakesslowerT3 Ford Mustang EcoBoost gains Ford Motorsports or Brembo brake kit options, +100 lb.
T3 Request to Add the FR-S/86 and BRZ Spec Lines to T3 #25888weightfasterT3 FR-S/86 and BRZ: wheels to 17x9, tires to 255, weight to 2750 lbs.
T3 Request to Clarify BMW SpecE46 Tire Verbiage #26027tyres & wheelsneutralT3 BMW SpecE46 now permits any DOT tire up to 225 width as alternate to spec tire.
Best is the class's fastest lap in that event's qualifying or race sessions, with the driver who set it, how many cars set a time that session and how close the top five were; a best from fewer than three cars is greyed. With two or more classes, "vs" is the gap of each class's best to the first class's at the same event. "% of STU" is the class's best as a share of STU's best at the same event (100% is level, less is quicker): weather and track condition move every class together, so this compares across years where the raw times do not. It still breaks when STU's own field changes or one session was wet and another dry. Newest event first. The coloured figure under each value is the change from the previous event that has one (green is quicker, red slower). Whole laps only, so events with different sector layouts still compare. Weather and track condition are not accounted for.