Yes while this is with a gas powered car, it applies here. Look for one in good condition. I received a 85 500SEL for free. It wasn't in good condition. So far I have spent $3400 bringing it back up good mechanical condition. As far as cosmetic condition, it still has the rust and bad upholstery. So look for one that's been taken care of and in good condition.
Oh and stay away from the 350SD and the S350.