I have a 2000 s2k with eibach springs, 17'' wheels with ap2 stock size tires, k&n intake. I was wondering which class I should compete in considering I am almost stock.

 

"Almost stock" doesn't count in autocross. I think you can make B Street Prepared though. You will not be competative if anyone has actually set up their car for BSP in your region though.

Unless you want to undo all of those mods (none you listed are legal in A Stock), don't plan on being competative. Just focus on learning a lot about car control and having a great time

 

I believe the springs and the AP2 rims bump you to BSP.