This is a copy/paste from a thread I started in the W124 forum:
I feel it is important enough to announce to everyone, and I encourage other frequently posters to the various forums to inform your fellow members.
My car began exhibiting ignition tumbler failure yesterday. I pro-actively removed the tumbler (not waiting for complete failure, and the inability to turn the lock to position one for removal), and went to the dealer this morning. I knew to bring proof of ownership from previous key orders because these are TRP (Theft Related Products) items. This includes ignition tumblers, keys, door locks and other similar things.
Imagine my surprise went I am told that TRP items now have been mandated by MB-USA (not by the dealership) to be "service related" items. That the car must be checked into Service to be ordered, and must be installed by Service. No longer can an individual just buy, and take home to install...even a key!!!
So I played a game of "pretend to start my car" with the Service Manager (whom I demanded to talk to). I turned the tumbler to position zero, pulled out the key, and asked him to "start" the car by turning the tumbler. It would not twist what-so-ever. Then I explained why attempting to use my car with a broken tumbler is a disaster waiting to happen.
I also asked what will happen when a customer has lost their key, and needs to order a new one. Will they need to tow the car to the dealership since the car cannot be driven without a key? He had no good answer to that, acknowledging that the new mandate creates many problems for them.
Since I am well known to them, having ordered often from them, they will allow me to take the part home to install. I will just need to drive the car back to the dealership to verify that it really was installed in my car.
Well, it's true. Started this year.
If you want a new key, new tumbler or anything by VIN you need to
go to the dealership, the parts guy has to have a service advisor write
a repair order, see your current (not expired) registration and drivers license.
I can tell you this will be 1 to 2 hours of time, because the service advisor
will not make you a priority to put you and your car into the system to
generate a repair order.
Good luck to those of you needing a new tumbler or spare key.