LOL, it would be impossible for Porsche to prove an exhaust tip would cause an issue (because it wouldn't), especially with it being behind the mufflers and not really part of controlling air/fuel or back pressure. This is more of a "I don't don't get to charge you mark up on the parts and only get to gouge you on labor" response. I fully believe in using the dealer for service in most cases, but an answer like his defies common sense.