on my car i have 40's flows and my first pipe was a prochamber, sound was pretty good but not what i was looking for. got a UPR x pipe, did not like it. so i got a OR h pipe and loved the sound but i eventually got bored and got the BBK x pipe i have now, and i'm going to ditch it to go back to H pipe. its a cookie cutter exhaust for mustangs with H pipe and flows, but it sounds great and X pipes just dont sound good with flows. if you want to do a different style muffler (turbo/strait through or race bullets or something) then an X pipe will sound wicked but with a chambered muffler H pipe sounds best.

so my answer, is i prefer H pipe with a chambered muffler. if you get a different style muffler then an X pipe will be good but not with flows.

well, I guess I'll go with the MAC o/r h-pipe since there are a lot of ppl that love the setup and I think that I will too. I hate to let a deal that good go by, but I'm worried that it will be too quiet and not aggressive enough for me. Maybe some otherday.

I have a MAC Prochamber Offroad H Pipe. I highly doubt that it gained any power over a non prochamber H pipe. I bought it for the sound. It really sounds great with both LM1's and LM2's. LM1's were still really loud and the cops kept giving me warnings, so I switched to LM2's. $210 is a hell of a deal, Do It. I bought my prochamber H pipe close to the time they came out and paid around $400 for mine.

prochamber is NOT an h pipe, nor is it an X pipe (but if i had to call it anything it would be an X pipe). as for power gains there will be no noticable gain over an X pipe (which is what it closely resembles).

h and x pipes at BEST just offer power in a different section of the RPM band. X pipe helps flow a little better in higher rpm's as the H has trouble passing exhaust over the long crossover between the 2 sections (where an X pipe merges it easily transfers gas to whichever tube has the least amount of pressure). but because its slightly more restrictive the H pipe will give you a TAD better feeling in the lower RPM band. power differences are not worth crying about or trading pipes out. SOUND is the only real reason to buy one of these pipes unless you have a full blown drag car doing bracket races and you have to be concerned about making every single horsepower count.

thats it. sound is slightly different from an X pipe but gives the same fast paced pulses, just sounds a little cleaner. there will be zero worthy power over an X pipe, and maybe a hair over an H pipe near the top of power band.

I have a prochamber it sounds very good but is a prochamber quieter than a regular H pipe?

I'm changing just for the sound...and yeah, the prochamber is more muffled than the o/r h-pipe and I've heard that the h-pipe is even a little louder than an o/r x-pipe...just what the muffler guy said.

Yes it is a little quieter than a o/r h, because the "chamber" itself acts much like a muffler.

Call it whatever you want the box says right on it Prochamber H-Pipe

H-pipe
 

I have the Mac Hpipe with flowmaster american thunder un-catted and my wife complains "it's too loud" That lets me know it sounds pretty baddass

Wait, do you have Mac o/r h-pipe or a Mac o/r prochamber? Your sig says prochamber