Gibson is the way I'm leaning having used them before(they are the quietest without sacrifing flow).I'm going to check the $$ difference of buying just the muffler and having it done or just buying the kit.A lot of people like Flowmaster.Iv'e used DynoMax before(they are tested to flow better than Flowmaster below 3500rpm)on a 2 V8 Dakotas and on my GW.I found that case length(shorter = louder) determines your sound/noise level.
Borla is a high quality part made of polished stainless.