I can't help you for your question....but about the W210, I might be able to help.

You need to clear the codes from the TCU. Even if you were to change the entire transmission, so long there is a code (doesn't matter what code) in the TCU, the car will remain in limp home mode.

Find a indy who can read the code from the 38-pin diagnostic port and clear it. Your car should drive.