Go to the following thread for additional details on replacing the ignition cylinder lock. The dealer will need to see your vehicle registration to verify that you are the owner. You can probably fax a copy to the dealer. The key for new lock cylinder will match your old keys; however, using an old worn key tends to cause problems with the lock cylinders. I purchased a new key for our 1991 300CE to prevent potential lock cylinder problems.

http://www.peachparts.com/shopforum/showthread.php?t=100458&highlight=ignition+lock+cylinder

__________________
Fred Hoelzle