A loudmouth exhaust with off-road X (or H) on a Mustang is VERY loud. My car has one. Here's a video from a racetrack with my car - you can hardly hear the car in the other lane, and its closer. FYI...the engine sound you hear at the beginning as we were staging is all my car: NMRA F/S Finals from KC

 

Heh, sounds like a mustang. I'll be emailing these videos to my buds if you don't mind... Not sure if you've got some kind of copyrights or anything.

 

Knock yourself out. They are part of the race coverage that www.stangcrazy.net provides for all the NMRA races. There are several more, though that is the quickest pass my car has ever made, and thus is my favorite.