I'll have to agree and disagree. Street racing without a doubt should be illegal. If you're any good at it, you're zoned in and wouldn't be able to stop if a non-related bystander/car got in your path. However, pulling people over for doing things to their car that makes them faster (exhaust work) or makes them look faster (tint, fart can) is ludicrous.
Why don't they ticket people who go to they gym, take karate or boxing, or people who buy a gun? All these things if used incorrectly are very dangerous. If I drive my mom's minivan recklessly, I'm going to get myself in trouble. Ticket people for racing, not looking like racers.