I'm feeling gleeful. I bought (off craigslist) a 1978 Mercedes last Saturday. I'm quite happy with it. It's a diesel, and I'm planning to run it on the home-brewed biodiesel we make.
When I first looked at the car, it seemed that there was some sign of oxidation starting on the paint job. ( It didn't show in the photos online.) But what the fading white areas on edges of the car turned out to be was somebody's careless buffing--IOW, unremoved wax. The paint is perfectly fine, after 2 hours of washing/ re-waxing. It's a beautiful-looking car.
It's got a few issues to deal with on the inside, but they are not impossible. The engine is great and the car is in wonderful mechanical shape. I got it at a decent price ($3k), so I'm getting the inside fixed right.
Here's a pic of my new baby... but it's my 15-year old son who is drooling.
bebu