Not the usual H-pipe question?

I read an article in Peterson's 4x4 and offroad where they dyno tested a POS chevy truck with a whole bunch of different exhaust configurations and the X pipe made the most torque with the 2nd highest horsepower, the H-pipe had the most horsepower and 2nd highest torque and the independant pipes got lower numbers (the truck had like 10 more ft/lbs of torque w/the h-pipe). The purpose of the H-pipe is to increase scavanging by equalizing the two pipes. I've also heard that the closer you get it to the headers the better the effect they have, but I don't have solid numbers on that (i read it in a exhaust/induction science oriented book). It probably is worth your time to put one in, but i can't give you any solid comparisons related to mustangs. good luck