Don't be scared by the hydraulic rear suspension on the 560SEL
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.