Took my 300M in for service yesterday -- among other things to have the inoperative driver's window fixed (it had never given any trouble until we went on a car-free two-week vacation, but when we returned the window no longer worked: lights dimmed slightly, and a click could be heard, but nothing moved. Did the lubricant thicken? Was the car sulking?).
I told the service advisor that I had heard of power window problems with the early 300M models. He said there are still far too many occurrences, unfortunately.
-=- Alan