westgastang4.6:
Borla XR1 (3.5" or 4" dia. round), SLP LoudMouth 1's or 2's, MagnaFlow MagnaPacks (4" round) are pretty aggressive especially with an o/r pipe. I had 'Packs but swapped them out for the regular MagnaFlow (oval) mufflers -- my old ears couldn't take it, lol. If you have the stock intermediate pipe with all the cats and resonators, the 'Packs sound mighty fine, imo.
Chris
p.s.--Welcome to StangNet!