Well you aren't going to get a turbo sound from a non turbo, but to get a deep, throaty exhaust tone you can go with a Magnaflow muffler with 2.25" piping.
This is my setup on the 4A-GE. Granted, its not a 7A-FE... but it's an ST!
2.5" under-axle to a Vibrant Performance muffler.
1991 MR2 - T-tops - Crimson Red - Gen3 3SGTE - Lots of moneyI'm not really an asshole, but I play one on the internet.**** Photobucket
not sure about the other engines, but my 5sfe loses power (didn't have any to begin with lol) when i changed mine to a 2.25" catback with a sport muffler