If I'm not mistaken, doesn't changing the wheel size from stock put you in prepared class? That's why I'm trying to stay with the stock size wheels. I'm really hoping that Hoosier will come out with a 19" tire. I'm pretty confident they will when the C6 Vette hits the streets and the autocross tracks. The Vette tires are wider but I think once they start making 19" tires they will make a good variety of sizes.