i was going to buy a mac catback in a couple weeks but dont know if i should get the 2.5 or 3 inch system. can someone help me choose? is there a power/sound difference between the two?
Unless you have plans on running a really high boost twin screw (25+psi) in the future I think you're better off with the 2.5 inch. The 3 inch is overkill unless you are passing some serious spent gas. You need to maintain a small amount of back pressure for the engine to run at peak efficiency.
I gained 2 mph consistently with the MAC 3" over the 2.5 Stinger kit I had. I also noticed a considerable seat-of-the-pants difference top end. I did lose a little down low on torque on the dyno, but it pulls harder up top.
I do have plans for a twin screw though and that is the only reason I got the 3".
But for the record, before the 3" I ran 120, now I run 121.5-122 consistently.
I like the 3.5 tips the best, but my old Borla 4" tips looked sick. If you do go 2.5 though, buy the SLP double wall tips....those are awesome. I even have a brand new unused set if you are interested.
Wow, you had a complete 2.5 inch system (X-pipe & cat-back) and then swapped it out for a 3 inch system? Both systems utilized the same mid-pipe? Catted? Uncatted?