Yeah not many companies make H-pipes. Wierd but its true. Yeah MRT makes a great H-pipe but it is friggen expensive, although sadly, i'd probbaly pay it since they are the only H-pipe manufacturers practically...
MAC and MRT i think are the only companies that make them...and maybe Mustangtuning makes their own, not sure. and I THINK...THINK BBK might make one...
JBA makes them also, but they're only for use with JBA mid-lengths, which coincidently, are more expensive than most Longtubes. In fact I think* JBA might make MRT's H-pipe for them.