Yeah there's definitely an increase in sound over stock. Here's that set-up I was describing, back when I had the manual GT takeoffs (and smoked lights):
http://www.youtube.com/watch?v=DJa2RJR9p4Y

 

voted for cai/tune. You can get a JLT cai/tuner from american muscle for 529 w/ free shipping, a ford racing or C&L is a little more. Out of the three, I think it comes down to looks, whichever you think will look better under your hood. The tuner and tunes are the same for them. Bama tunes with free tunes for life.

http://www.americanmuscle.com/jlt-sct-0509v6-kit.html

Get the cai/tuner first if you want perf more than looks.

 

CAI/Tune = more go than show

Dual exhaust = more show/sound than go

With that said I went duals 1st (manual GT takeoffs & x-pipe) then CAI/tune.

 

CAI. The above vid of exhaust is really quiet to me

 

If you're going for sound, go with an H Pipe being the X Pipe really doesn't give you any gains.

 

CAI/TUNE
Your BUTT DYNO will thank you before your ears will...