My Borla's sound awesome but are definately not loud. I have my stock 6 cat h-pipe on still, though. I agree with Cravnpup on the Magnaflow. I've heard cars with them and hiflow cats (at car shows and what not) and they sound pretty mean.
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66 Tahoe Turquoise Coupe
Laser Red 96GT Ragtop
Both are slow but easy on the eyes!