I've kind of had my eyes out for a W220 lately, and I spied one at a local dealer as I was driving by today...turns out it was an S55

I stopped to talk to the sales manager and it's got 150k miles and he's asking $7800. He said it used to be his personal car and everything on it works perfectly. I've done a little googling on the W220s and especially with the AMG models, people say go 2003+. Could I get some input on what exactly changed in MY2003? I know the ABC/Airmatic suspension is always something to watch out for...anything else I should know to look for? For the mileage, how is the price, and what should I try to negotiate down to?

I really want to go for a test drive, but I'm afraid if I do there'll be no turning back so I want to make sure I know what I may be getting into before making any rash decisions.

Thanks!

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1963 Ford Falcon Convertible
1972 220D 4-speed
1986 190D 2.5 5-speed
1999 300D