ok.. now the OHV does not sound like a ricer, its one of the best sounding V6's that you'll find. I personally haven't heard a lot of SOHC but I don't see why they would be too much different.
Anyhow, I'm a fan of Gibson cat back exhaust systems. They definately improve performance and you get a real nice sound that isn't too loud.. why you stand on the gas it sounds "beefy"..
Another option, which is also the cheapest would be to get a 2" or 2.5" internals long cherry bomb glass pack.. It will definately be louder than any muffler but these engines aren't that loud with no muffler as long as you leave the cats on it.