to be honest it's all a preference. x has the exotic sound and the h has the classic muscle tone. we can go around all day and battle over which makes the most torque and hp's at the lower, middle, and high RPM's. Don't get me wrong there is a difference. The difference is not very much SO it all boils down to what sound are you looking for.
I went with the X- RATED and love it.
my combo is the ford shorties, bassani high flo x pipe, magnaflow mufflers.