My dream car
Hey Apollo, did you say a 1983 CD turbo? That's my dream car. I want that, and a TD, to go with my SD, and then my stable will be full.
If you don't know much about diesels or Mercedes, try to find an Independent Technician who will look at it for you.
You will have to repair things as you go along because of the age of the car, regardless of how great your tech thinks it is. Don't be surprised or disappointed.
CTH has some great advice about the body. The front and rear of the Rocker Panels will tell you a lot. I would not buy any Mercedes if the floor pans were rusty or "soft". Mercedes are known to leak around the window seals and older ones often have water sitting under the sound deadening material under the carpet. Even if the floor pans look good from outside the car, I would advise taking all the floor carpet pads out and snooping around inside the car. If the Rocker Panels have been repaired they may not have fixed the inner frame rails and you will see this from inside the car.
I hope it's a nice one!