Ok if I went and bought this:

http://www.americanmuscle.com/pypes-...t-9604-v6.html

would I have to replace the mufflers to performance ones or would i get good sound + performance?

 

You don't wanna buy that.

Dual exhaust, with an h,x,divorced, or other type of mid pipe is what you want.

 

Rule # 2 applies here: He doesn't want to spend 400, and H pipe setup would probably cost around 400 if not more(if im not mistaken)...unless he finds some really cheap! I got my LTs, H pipe, flows 40s, and it was around 800.
I say better save some money and get true duals, because after you get a single system you won't be satisfied for sure. You will probably want something more and that will cost more than it usually would!