I wrote: "all but did away with the "Stock" classes"
Can you clarify this statement, because this makes it sounds like they still exist
Sure! There is still Super Street-R. The following cars remain eligible to compete on R compound tires:
Alfa Romeo
4C (2015-16)
Audi
TT RS (2012-13)
BMW
M3 & M4 (F80/F82 chassis)
(2015-17)
Cadillac
XLR
Chevrolet
Camaro SS 1LE (V8) (2017)
Camaro Z28 (2014-15)
Camaro ZL1 (2012-15, 2017)
Corvette (C6, non-ZR1) (2005-13)
Corvette Grand Sport (C7) (2017-
19)
Corvette Stingray (C7) (2014)
Corvette Z06 (C5) (2001-04)
Dodge & SRT
Viper & Viper GTS (non-ACR,
non-TA) (2013-17)
Viper (non-ACR) (2008-10)
Viper SRT-10 (2003-07)
Viper GTS (1996-2005)
Viper R/T (1992-2003)
Ford
Mustang Boss 302 Laguna Seca
(2012-13)
Mustang Shelby GT350 &
GT350R (2015-16)
Mustang Shelby GT500 (2007-15)
Jaguar
F-Type (non-Project 7) (2014-16)
Lotus
Elise (non-SC) (2005-11) (see Appendix F)
Evora S (2011-14)
Exige (non-S) (2006)
Mercedes-Benz
AMG (NOC)
Porsche
718 (all) (2017-19)
911 (991 chassis; non-R, nonTurbo, non-Turbo S, non-GT2,
non-GT3) (2015-17)
911 (991 chassis; non-GT3)
(2012-14)
911 (997 chassis)
911 GT3 (997 chassis, non-RS)
911 GT3 (996 chassis)
911 Turbo (930 chassis) (1974-89)
Boxster (all, incl. Spyder) (1998-
2016)
Cayman (all, incl. R; excl. Clubsport) (2006-16)
Boxster S (2009-14)
Boxster Spyder (2011-12)
Cayman GT4 (non-Clubsport)
(2016)
Cayman R (2012)
Cayman S (2009-14)
Tesla Motors
Roadster (all) (2008-13)