i am in the middle of purchasing a magnaflow 14816 or 14862 for a friend of mines who owns a 2004 545i, he trying to do quads on his car. he already purchased the m5 bumper, now can i purchase one of these mufflers to do the set up he want? someone told me we could remove the pancake resonator in the middle of the car and replace it with the magnaflow and run custom pipes to the back with custom tips, is it as easy as this ? sorry to bother just trying to help a friend out that is not on the forum, cause it it was up to me i just tell him forget the quad and go with the RPI exhaust like i did lol, i Love it.....