While I like the Magnaflow straight through design, it still has some tin-can raspy sound to it. I've used the Aerochamber in the FD and other cars and was amazed on how much the noise went down during idle and cruising, but at WOT it didn't sound like some cheap tin can muffler.
BTW, I bought Cayenne D-shaped tips for the GTO which appears to fit perfectly in the back.
Pics will come soon once I have it installed....
http://www.v6z24.com/mods/howto/images/mufflerchoice/muffler_hp.gif
http://www.v6z24.com/mods/howto/images/mufflerchoice/muffler_db.gif