Hi, I sure could use some help/advice with some changes I'd like to make on my 2006 SLK 55. It's already chipped, has a set of headers which removed the first set of cats and has a Needswings intake. Next thing is an "X" pipe and new speakers to replace the ones between the seats. The dealership wants a lot to install 2 little speakers and there have to be some aftermarkets and instructions out there. Also, "X" pipe prices seem to be kinda' all over the board and European ones can't be shipped to the U.S.? Also, the 18' Michelin Pilot Super Sport rears lasted a grand total of 4887 miles which prompted a mileage warranty of $340 from Tirerack.com but still, the ago old question of balance between what sticks and what lasts. Any advice from all you more knowledgeable SKL 55 owners out there? I'd sure appreciate it. Thanks.