There's absolutely nothing wrong with staying stock! Driving a car with an understeer imbalance on race rubber (or even street tires) with make you a VERY good driver because you have to keep the front end under such exquisite control all the time, and not jerk it around at all. It also forces you to take a slighly exaggerated line, so "getting early" on the course becomes second nature. It can be frustrating to know that you're not using the potential of the chassis, but if that doesn't bother you: by all means, save your money!
