Don't street race, rise above it. It doesn't bother me if I let some dork think he gave me the pipes and intimidated me. I race him I look just as silly.
Yeah, TripleB, it pizzes them off to more of an extent if you just laugh and drive off slowly. Ususally they'll try to give you some "lesson" on how wicked their car is right in front of a Cop, into a curb or tree.
Take it to the track, you can find all kinds of people that want to blow your doors off.