Right now my setup is h-pipe with 2 cats and they are both gutted out and 2 flowmasters. I want to get an o/r X pipe and spintech pro street mufflers. Which should i do first, The mufflers or the x pipe, Which one and i goint o notice a sound difference in the most? Also ifi keep the same mufflers and take out the h pipe with gutted cats and change it to an o/r x pipe will i hear a difference in just doin that? Thanks everyone