I can't help but comment...I learned to drive on my parents' 1980 505SD (no, that's not a rogue D; it actually had that insignia instead of 505S and the "diesel" plate below it). I think the Peugeot made me appreciate that a diesel engine in a car was a lot of fun.
Mine was a 4-speed manual and felt slightly peppier than the W123 240D (it's lighter, for one) which I think is partly why my parents chose it instead of the Mercedes.
However, my "classic" Mercedes gets respect from onlookers, while I got lots of ridicule from my friends when I drove the Peugeot.
Nonetheless, the seats were wonderful, the shocks (when you have the proper Peugeot ones) were fantastic, and the engine was quite reliable. We had a defective aux fan and alternator when we bought the car (new) in 1981. Since then, there were many misc. electrical problems that would come & go(power windows, lights, various relays & switches, etc), the sunroof broke over & over, and when the water pump & head gasket failed at 105K my mom got rid of it. It was hard to find someone to work on it and expensive to get parts after Peugeot left the North American market.
I knew the people we sold it to and they drove it for about 20,000 more miles before the engine "blew up." I never found out exactly what happened, but they put a turbodiesel in and then a year ago, I saw the car on Craigslist. I was very tempted to buy it back
So if you get this one - when you need parts, check the Seattle craigslist....there is some guy up here that has a LOT of 505's parts and could probably ship you stuff cheap.
Make sure the cooling system and aux fan are working perfectly and the head gasket is OK. Head gaskets were even more of a problem on the turbodiesel engines. If all that's OK, it should be just as reliable as the Mercedes engine.