S500 Coupe
 

Anybody knows what MB changed on the S500 coupe on 1996-99 models,versus the 1994-95 models of the same car.It got better? or just cheeper...

If you do a search, you'll find an earlier posting I did on exactly this issue.
In my opinion, the changes made in 96 on were for the better.

It seems to me the early cars had less power assist in the steering and a little better road feel. Through the 95 MY it was an LH engine management system - distributor caps and rotors, replaced by coils in 96. The caps and rotors are about $200 every 60k miles or so - might seem expensive but bulletproof and easy to do. The newer system is theoretically more reliable but also more expensive to fix. But the big difference is the transmission - the troubled 722.6 started in 96 - seems to have half the life and twice the rebuild cost. I personally subscribe to the "never buy a Mercedes after 1995" theory but also subscribe to the "never buy a car with ASR" theory, and all S500 coupes had ASR so to me it's a moot point.