Hmm.. has this been posted in the wrong topic? Makes no sense! There's nothing wrong with the original motors in 300s - I seem to remember theyre made by a German company, several car manufacturers use the same motor in their mechanisms. The problem in window motors failing is through lack of use - use them more frequently and they're fine.
The central locking in my black car has never worked - I never got down to fixing it either. I did replace the drivers actuator and that made no difference, unless I was unlucky enough to have two faulty acuators - unlikely? Check the wiring between the door and body of the car too - theres alot of flex going on there. I do have a spare actuator, but I have no idea if it works.
Other than that, I think the gauges have sold
)