I have just completed a rebuild of the engine on my 1981 300D and seek information on the engine vacuum control system. I have two diagrams on the system. One shows a restrictor in the line operating the vacuum control valves for the transmission modulator and the other has no restrictor. Are there difference between cars delivered to various countries across the world and if so what are they?

I also am looking at electric locking for the car as I wish to operate it remotely. Can some kind MB enthuisast with experience in this please enlighten me as I am finding difficulty in geting sensible answers to this problem here in Australia. Thanks for any assistance.

Not real sure of your preference, but you can operate remote locks using the existing vacuum system. There are a number of old posts on the subject, check the search function for threads on that.