This guys has an MRT catted h-pipe on his E-Force supercharged 5.0 and he like it(GoT midlife CS
I have an 08 GT with the MRT H pipe. Many people buy an X for a very light HP improvement. I picked the H because it sounds a lot better to me. MRT makes a really quality product. It is also 304 full stainless unlike others with 409 iron mixed in and eventually rust out.
It has been shown that there is pretty much no difference in power between x-pipes and h-pipes on the 5.0 mustang.