Don't do it!
First, this sounds like the first Mercedes that you've gotten serious about, so you have a limited perspective.
Second, this is a lot of miles for a car that's got to get you to work every day. Unless you can verify the mileage on the transmission and what components have been replaced and when, you could well be walking into a deferred maintenance money pit.
Third, this is an S class, top of the line. But also the one with the most expensive electronic and vacuum gizmos to wear out and fail.
Fourth, for a the same money or a little more you should be able to find a car with less than half the miles
All MHO, and I am sure others will express themselves on this.
Falls Church VA
'66 200, '66 230SL, '96 SL500. Sold: '81 380SL, '86 300E, '72 250C, '95 C220, 3 '84 280SL's '90 420SEL, '72 280SE, '73 280C, '78 280SE, '70 280SL, '77 450SL, '85 380SL, '87 560SL, '85 380SL, '72 350SL, '96 S500 Coupe