I have yet to find my '99 W210 with 100K miles to show poor quality, and would gladly get a newer one, but would probably shoot for '02 to give the '00 dash electronics time to have the bugs worked out. Obviously high-mileage cars need some attention, and Mercedes definitely have idiosyncrasies, but that's why you like them.
Get a V8 if you like acceleration.

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Prost!