All the advice given is very valid in terms of which car might be the most trouble free.
I have owned and enjoyed 45 German cars in the past 12 years. I currently drive a 1994 C280 w/ 116,000 I bought for $5200 from a dealer.
1. ANY dealer, MB or otherwise wants to move product...period!
2. Private party owners generally view their cars as their "baby" and feel they should get their investment money back with price.
The dealer paid under $3000 for the 560sel. He knows the car will be very hard to move with that mileage and color, REGARDLESS of records. Remember it's just a piece of metal to the dealer and not his pride and joy. If he does not move the car after a certain amount of time, it will go to auction where he will only get about $2200 if he is lucky. Wait til the end of the month when non-selling cars go to auction and offer about $4500-$5000 cash. Remember, it's just a piece of metal to the dealer and it's his job to sell cars. Don't be fooled by the glitz of the showroom, shop or good cop/bad cop bartering techniques. The 560sel is NOT worth more than $5000.