larrysellers, I recently bought a used VMS 02 IB on this board and sent it to Schoeps for checkout and repair; they returned it last week with two things fixed (one electronic, one mechanical). So they do still repair these at least some of the time. There may be some things they can't fix any more, I dunno, like if you run over it with a steamroller and then ask them to replace 100% of the parts. But there isn't a total ban to be sure.
Edited later to add: Sorry to say, in mid-2018 Schoeps discontinued nearly all repair support for VMS-series preamps.
--About preamp sound: I don't hear differences among preamps that I would ever use--the ones with very flat frequency response, low noise and distortion, adequate input impedance, common mode rejection and overload margins, proper phantom powering and no "pin 1" problem. It's possible to get all those things right and achieve sonic transparency for all practical purposes--and that's the approach I favor.
Certainly there are sonic differences among some preamps, and maybe 50+ years ago that situation was unavoidable. But nowadays it would only be because some people want and expect there to be such differences, so some manufacturers deliberately give their products a distinctive sonic "character" or "signature" of some kind. The only problem is, any deviation from neutral can (at best) have a favorable effect on the sound only sometimes. In other cases any given flavoring will make the sound "different, but not better," while in still other cases it logically MUST make the sound worse.
Imagine if you had an audio circuit that made ALL signals "sound better" regardless of what you fed into it. You could use it on ANY pre-recorded signal, store the result, then put that result through the same circuit again, and the signal would by definition come out sounding even better the second time around. If you then repeated the cycle further, the sound would keep sounding better and better indefinitely.
If something about that scenario sounds wrong, you've taken your first step into a wider world ...
--best regards