My 2 cents -
I just got a 88 - 560 SEL - $5000 have since put in about 1500 in tires, valve gasket, front brakes, air and new OVP.
These cars look great and drive great too!
Trick is - what lies beneath. Am not a techie by a long shot - have it looked over by a trustworthy mechanic - that is your best bet.
Look for oil, smoke, the rear end should NOT sag and the fluid container (under the hood, to your right, behind the headlight) should be half full. A/C, electricals - rear seat reclines? Seats - springs etc, meaning they shouldn't be sagging when you sit on them. Timing guides, suspension should NOT be clunky and noisy.
Could land up costing you big bucks to repair, it is a nice car - my advice - have it looked over and don't be in a rush. If all these items are in top order, then 5+ may make sense.
Goodluck either way, you will love the car, you will hate the nagging repairs if they come about, but, that is true for any USED car.
This site is great, when you do get the advice, it is unbeatable, sometimes you don't. Search threads.