GMPP (GM Performance Parts) Performance Exhaust with an angled tip. My favorite mod so far. very very deep sound. doesn't sound ricy (sp?) at all. have yet to have anybody say they don't like the sound. also, all the videos of it don't do it justice. it sounds way better in person.
I guess that since i started this thread i should post what type i have.... I have a complete custom exhaust except headers, with two vibrant resonators one in place of the cat and the other where the stock resonator used to be, a flow master race muffler and a magnaflow 4" tip, 2.25" piping mandrel bent. some say its too loud and others say that it sounds a little raspy with no tone, but lots say that its nice!!!!
I've got the Magnaflow exhaust, but I modified it. It was a little too loud for my tastes - as far as aftermarket exhaust systems go, it was on the quiet side, but when I accelerated hard or went up hills it was annoying. So I bought a GM Cadillac Eldorado muffler for $35 on eBay with a 2.25" entry and exit and ghetto-rigged it. It doesn't look the best (it's a little too big), but it's quieter than stock and I've still got the 2.25" pipes instead of the small stock pipes.