Everyone has their $.02, and it seems universal that we say the prices are too high (See also Life of Brian, gourd-haggling scene). I think KBB/Edmunds/NADA sites give reasonable reference points that you can adjust based on deferred maintenance for the particular car.
The W211 there is the 1st year. I would avoid it for that reason, and because of the electro brakes they had through 2005.
The 4matic V8 will get pretty bad mileage, so bear that in mind.

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Prost!