With the H-pipe you retain much of the Mustang "muscle" sound. With an X-pipe it will become a more exotic tone. Some like it. Some don't. Personally I recommend sticking with the stock H-pipe for awhile as it flows nearly as well as an aftermarket X-pipe. Then if you want a change of sound go for the X-pipe. Just a thought. By the way, I have the catted X-pipe. I didn't like the exotic tone at first but now I'm used to it and actually like it.
;-)
i have a offroad X, and flowmaster catback dumped after the mufflers, and i love it, but when i do LTs im gonna get an H, and also have my X pipe cut and see which one i like better...ill let ya know how it goes