Yoshimura all the way . You can get a full system for under $700.00 . I got the TRS and I'm very pleased. If you have the money to spend then get the Akrapovic, but you get just as much bang for yor buck going Yoshi.
P.S save those bucks for turbo .You'll probably want one later I know I do and that way you wouldn't have spent all that money on something you won't need anymore .