We own a similar car (1983 280SL), which we bought last year from the original owner, who bought it in Germany and imported it himself. It's a great car. The smooth inline twincam six combined with the 5 speed manual is an excellent powertrain. I have had no problems getting parts for the car, but admit that I haven't had to do anything major to it. Ours has about 80,000 miles on it and runs like a top. It met Denver emissions standards when we bought it. We don't have emissions testing in North Dakota!
I would certainly have it inspected by a competent mechanic to be sure it doesn't need anything major. The valves need to be adjusted periodically, but that's easy to do.
I hope you like the car as much as we like ours.