If memory serves, 126 and later keys are different than 123 and earlier keys, and need to be done by M-B.

BTW, those keys that some of you have found at a locksmith that work, do they work as a master key, or as a valet key? If they work as a master key, does anyone know where the blanks might be acquired (operative word: "blank"; I cut my own keys)? Every place I've been to that cuts keys doesn't have any blanks for M-B's.

I've mentioned this before, but I'll say it again; maybe it'll help someone if they can't find any 123 blanks around. I've found that a key blank for some Hondas can be modified to work in a 123 lock cylinder. The only thing is, it will work as a valet key; you won't be able to open the trunk, passenger's door, or glove box with it. They work the driver's door and key switch just fine, though.

You need to take your 123 key and hold it next to the key blank to see how far the rear shoulder needs to be cut back. You then need to cut the rear shoulder on both sides to match that; go too far and the key may go in too much; don't go far enough and the key won't go all the way in. Once that's done, it's just like cutting any other key.