If you cut muffler out do straight 3.5 pipe will it hurt the truck and does it help out any with the performance i dont have any mods but will soon need help on the best mod for my 7.3 167,000 and counting
<!-- / message -->

 

Mine isn't a powerstroke, but upgrading the pipe and removing the muffler wont hurt anything. I have a 3" down pipe, 4" exhaust with no muffler into 5" stacks. The larger pipe will help performance and lower your egt's. It wont be very loud though as the turbo acts like a muffler.