My sb 408 has a 2 1/2" x-pipe system from hooker comps, to an x, through $18 summit turbo mufflers, and a quick turn out in front of the wheels with 4"tips.

The car is a little rumpety loud and has bass at idle, and she's incredibly loud on decel. (4 spd) especially @ 4-5k rpm, but is actually pretty quiet at cruise. It is nice to be able to feel like I can drive kind of quiet.

Any time I'm in the city I am reminded the car is not quiet- the buildings really keep the sound in.