if you go with long tubes i highly suggest not going with an slp cat back. i had an o/r X and the slp loud mouth 2s on my gt and it sounded good for the most part. at the end of march i had LTs and o/r H installed and 3 weeks later the slp kit was replaced with a set of dumps. it sounded like complete shit. im surprised i didnt get pulled over for how insanely loud it was, well that mightve been because i couldnt stand the sound of it. the best way to describe the sound is it sounded like a harley, but even raspier. im running a full MAC system: LTs, H, and dumps. ive gotten nothing but compliments on how it sounds. my buddy has an 04 mach with an o/r prochamber and mac catback and its one of the best soundings NA 4Vs ive ever heard. pretty much the only time id suggest going with an slp kit is if you dont plan on changing anything besides the catback. hope this helps, if you have any questions let me know.