A buddy of mine build a 1989 nissan 240sx for drag racing and swapped in a turbo engine from the jap equilivant car. I couldnt tell ya what size the engine was but it was a 4 cyl rear wheel drive.
ANYWAY he had an exhaust cutout for racing but on the street he used this muffler and it had a deep throaty sound like a little corvette. I recall him telling me it was a cheapo from autozone or something.
http://www.holley.com/types/Raptor.asp
I tried one on my 2.8L v6 S-10 pickup, and it sounded good as well. I noticed it was fairly quiet until I got into the upper RPMs. Just a sugestion.
Oh by the way mine was 2.5" inlet/outlet.