I have a 85' 380SE, which is essentially a "shorter wheelbase" 500SEL, with a smaller engine (3.8L vs. 5.0L). I have nearly 270K on mine and still running decently. I have a engine misfire now that I am trying to tackle. Its been a pain in the neck. Still does not burn or leak any oil of any kind, which I also find amazing.

As far as body goes, it is rust free (as expected for a southern car) and the interior is excellent (save for a cracked dash top panel- imagine that), but a cover over it does nicely. Electrical wise- also excellent (so far)- which seems unusual to me, (because all of the problems I have heard on older MB's in the past). All of the windows, lights, gages, odometer, trip odometer, etc. are in perfect working order.... I am just waiting for something to go bezerk.

I did have a problem with water getting in the trunk and RR floor panel, but a new antenna seal took care of that problem at once. I also had a recent and massive power steering leak from the steering box. New seals were $22. and I had to pay my mechanic $50 to replace. I am also currently needing to install a new thermostat.

Enjoy your new 500SEL. I really like the longer wheelbase model.