I really can't understand why in the world any MB dealer would refuse to work on Euro MB's. Your '82 280SEL is a W126 chassis with the same engine used in the 280E, and W116 280SE(both sold in the USA) so I can't see how the dealer would have problem working on the car. I could see the problem if you imported say a A-Class (not possible anyways), but what can they say about your 280SEL? Euro models are availble in smaller engines and with less fluff like leather seats. But in response to your question, I would say wait until someone comes by that can appreciate the car for what it's worth and won't be put off because MBUSA says you shouldn't have kind of cars. After all a Mercedes is a Mercedes even is it has cloth seats.