I have a 98 gt with a pypes o/r x and slp loudmouth 1 catback, and it sounds great. I like the way it sounds and it really compliments the cams. If you want to hear it I have a video of it in the exhaust thread.
Rebuild in the works. New crank, 2013 Boss rods, srp .020 over flat top pistons with valve reliefs, 12:1 compression, ported pi heads, comp xe278ah cams.