Im contemplating a new exhaust for the XF. My idea is to remove the rear cats and run a single pipe to the stock exhaust. I also want to open the muffler and remove all the insulation and the perforated kidney things inside then wrapping the muffler in sound heat/deading material . I am wondering of the possible negative effects on it. Is it goin to mess with the engine at all (backpressure). Im lookin for a deeper sound out of the exhaust. Thoughts and experience much appreciated! SORRY JUST REALIZED I POSTED THIS IN THE WRONG PLACE!!!!