X pipe or H pipe, again

I'm having a tuff decision on what to get. I was originally going to order a custom stainless H pipe from TTI, but all my buddies are giving me sh*t saying the X pipe will give more power. Now I've never personally done any testing to prove it out, but from what I read in many places theres not much difference in performance. It seems sound is the main difference. Does anybody have any first hand experience on performance from X to H pipes?