Hello, and welcome to the forums!
There are so many different opinions on what is "best" for exhaust. I suggest you search the forum for previous posts on this subject and make a wise decision based on that. You can search by using the "search" tab at the top in the tool bar. Just enter "exhaust" and you will find more than enough to help you out. Good luck. :cheers:
It depends on what your future mods are. What kind of HEADER did you get? A gen6 hotshot makes most power with a 3in exhaust on a mild/wild cammed motor. If you just plan on doing minor bolt ons with cams, go no bigger then 2.5. Consider piping size before brand names, not all exhaust are the same size piping which matters the most.
You know... the SE-R stock exhaust is pretty damn good though. You can run your header and intake and still enjoy a ton of power.
If you really like the aftermarket sound of an exhaust or just really want to blow another $500 then go right ahead. :thumbup:
But I must say I've been happy as hell with my SE-R stock muffler. When I punch it my stock muffler makes a nice low tone, i like it.