I have an '02 E46 and am running 18" Bridgestone Potenzas that need to be replaced. I have Bilstein coil-overs and camber plates added to the car and it handles great but feel I need more tire. I don't want to buy a third set of rims and would prefer to race the occasional autoX on the street tire. What should I buy? Also, can I or should I use a wider tire?