Comptech will give you the nicest sound. The GReddys and Flowmasters will be loud and obnoxious, as you said. In my past experiences, people that have loud exhausts usually get looks of disdain from people, not appreciation. get the Comptech...who cares if riceboys don't know it's an aftermarket exhaust, all that matters is it gives you the performance you want. Comptech will do that the best.
Oh yeah...pick up a set of comptech headers while you're at it. 20-30 WHP increase for $1200.