Stock class rules are basically, Tires, Shocks only not springs, Cat-Back exhaust and a front sway bar.
Tires, DOT approved R-comp on a stock size wheel. So whatever you can fit onto a 17x7" wheel +/- 5mm spacing.
Exhaust, has to be muffled and a factory cat. You can run a super trap muffler if you want, they are freaking loud, just cant have anything done on the exhaust in front of the cat.
Front sway bar is free.
Shocks are also free, you can have custom triple adjustable Motons put on if you'd like, you just wont want the price of them.
Your Tune, Camber Plates, Springs, and CAI alone take you out of Stock class and put you into a Street Tire or Street Prepared Class. I am not real sure of all the new ST rules.
Rule of tumb in auto-racing, if the rules don't say you can do it, you can't.
"I have made a bar graph of my favorite Pies and I made a pie chart of my favorite Bars" - Marshall Eriksen