I was at the dealer friday, sticker on a decently equiped E320CDI was $51,225. I didn't get the impression that they would budge much, not that I was going to buy it(I wish) but the don't hang around the lot thats for sure.
MB always runs a sale in December, they have been doing this for a few years.
I bet a 1991 560SEL with 50k miles on it is worth more then a 1992 500SEL with the same mileage. Old W140's are not worth much. My friend that owns the car lot offered me a 1993 300SE over the summer for $7,500. 130k two owner car, it was pretty nice. The body and interior were 7-8 out of 10. The evap core was done 3-4 years ago, and the head was just done after the head gasket blew. (po worked at a MB dealer, big bill for the head!) I should have sold my SDL for $8k and used the difference towards wheels.