I just installed my Borla Cat back last weekend, haven't hit the dyno yet after installing. Sounds good, more throaty, bout 30% louder, but a bit of drone in the interior at certain revs. But I guess it comes with the territory when you a install a "free er" exhaust. Nice bend, tig welds can be improved.Performance wise, I feel a diff. But then again I isntalled the Tom's drop in filter and Joe Z intake at the same time.