At most autocross events, their not going to check your class and then try to see if your car is within the rules of it. Obvious things like 19 inch wheels will get noticed. Unless your beating really fast drivers at high level events, just try to pick the class that you think you belong in. Chances are, since your driving a contour, your not going to be competitive in whatever class your in. Don't worry about beating as many people that can. Just have fun. The contour is a fun car to drive at an autocross. I've beaten many faster cars in raw time. Unfortunatly my car is in one of the mod classes, so my pax times aren't that fast. I don't care though. It's a lot of fun to drive fast.