Ok, I'm gonna finally make the final exhaust change. I currently run 2 chamber Flowmasters on a mostly stock 97 Cobra. I have a buddy that just put an off-road H on his 2001 GT that has 2 chamber Flows, Killer sound. But what about on the 4V??? Sound is important, but then so is the performance, can anyone advise on the question of X or H, with or without cats??