Well the perfomance exhaust for the 97-03 GP's bolts up to the 04's with no problems except having to cut off one hanger and get a new one welded on in a different spot. The piping is 2.5" all the way back with straight through mufflers. The car has nice mellow low rumble at idle with a nice howl at WOT. When your at cruising speed there is very little to no drone at all. Very pleasent inside when on the highway. As far as I know I'm the only 04 with this exhaust. Let me know what you think.

Fred