Originally Posted by
Hermes
We class cars with a simple system of model, year and modifications. We consider a BMW to be in Stock class if it has only factory equipment. In addition, Stock classes permit any size wheel and tire; non-stock shock absorbers, bushings and strut braces; any brake pad material (brakes must be stock-size), any air filter or cold air intake or catalyst-back exhaust; and only naturally-aspirated cars may use aftermarket engine management software. Tires must be 140 treadwear rated or higher in Stock classes. ANY other performance modification, including but not limited to springs, “R”- compound tires, and engine software for turbocharged/supercharged cars, puts the car in Modified.