Rockman59 prompts me to add that the 560SEL hydraulic rear suspension (the 300, 380 and 420 use conventional shocks) should not be a cause for fear if the PO's records indicate timely hydraulic oil changes. At 80-100k typically, per this list, the rear nitrogen cells ('accumulators') lose their gas and the car gets a pogo stick ride as a result. Replacing the cells ($100 each, vs $50 each for shocks) is very simple - easier than shocks IMO. The system is self bleeding, so once changed, replace the fluid and filter (the reservoir is under the hood and very accessible) and off you go.

I did the job at 90k and it was a breeze. I used the MB OEM hydraulic fluid, not knowing of compatible alternatives.