Congrats on your purchase... welcome to the forum..!
I have a '96 S500 Coupe. Nice cars, eh?
Differences I know about are:
1. Different engine (at least by MB number). '96 is all electronic engine controls... no rotors, caps, etc. Each of my plugs has a separate coil on its top. Engine controls all electonic; system has ODBII for diagnostics, etc.
2. Different transmission. '96 has the 722.6 electronic trans. Starts off in first gear instead of second, etc.
3. Climate Control head is different. All digital.
4. Radio is different, although same functionally. They modified the face a bit to match the climate control.
5. Think the '95 has the same offset wheels front and back. My '96 has 51mm offset wheels in the front and 34mm wheels in the back.
I'm sure there's more, but that's what comes to mind ...
I've got the MB S Class "Introduction Book" for 1996... its about 30 pages thick, so there are significant changes...