has anyone done this and how hard was it to cut out the bumper?Real AMG 55 mufflers are hard to come by and expensive- check Ebay often and you may luck out. However, if you just want the look of dual tips see Ebay Auction #330220862175. For under $500 you can achieve the look with a little modification.
I put Sl55 exhaust on mine. Cut off the quad tip and put on your single tip on and you do not have to modify the bumper. Don't make it ghetto, .