The H is generally louder than the X, the power differences will be splitting hairs. It sounds more old school muscle car where as the X sounds more new school nascarish.
I personally prefer the X because it is quiet when you want it to be and loud when you want it to be. The H is just loud all of the time.
Hundreds esp younger ppl said my bassani x/or and catback 03 is the best they ever heard so whatever trips ur trigger. Course that has a different firing order that even sounds higher than a 2011.
No plans as of yet to make a catted version or a short version for longtubes. This H pipe will be just like our X, bolts to stock manifolds and to any cat-back exhaust that uses stock location/size over axle pipes.
the pressure waves an x-pipe creates is why. there are no low pressure waves from and h. all of the power an h makes is from torque. an h pipe increases the effective collector area of the exhaust. an x pipe has the torque but also improves power. and x is louder because the low pressure waves travel down and up the exhaust.
that all an h-pipe does is increase the collector area. a larger collector increases torque, a smaller one improves power. a perfect collector merges to a point where there is no restriction and has a powerful pressure spike for scavenging, but also then increases to better torque. adding an h-pipe after that adds collector area. and torque. not HP. hp is a side effect of an h-pipe.