If you want an X-pipe, I say go for it.
However, most gains will be made with a properly sized, mandrel bent exhaust with good modern mufflers.
The X vs H has been a topic for a long time, usually any test that shows a runaway from one or the other had additional changes that weren't accounted for.
The X does sound cool if you like the sound, and if you want one, do it now so you don't have to wonder, but it won't be magical compared to an H with the same good exhaust.