Its easy to DIY. Search on here for lock cylinder, theres a ton of posts. Anyone can repl lock cylinder from MB for $100. Its when the thing jams up and you cant turn to pos 1 that you are screwed. IF you are lucky enough to have fair warning, I'd heed it now! If you really want to take it in to dealer, they will prob charge $250 or so, just tell them you need a new lock cyl. You have to show proof of ownership.

__________________
Paul
Benz-less
I need an SDL !