They all gotta go. Even a fancy paint job or too much chrome can expose your secret assets. Just don't go there, girlfriend. Stock wheels, a stodgy body-style, and faded paint all work to your advantage under most circumstances. Body and suspension modifications should be subtle.
Sticky meats are critical, but try to run something close to stock size.
Aftermarket performance parts should be blacked-out, hidden or painted. Limit chrome accessories. Think bland, bland, and bland. Slap a turbo on your Eagle Talon and cackle brightly when you smoke his sorry butt. If your goal is to become a player , however, you need to learn a more complicated game.