Saw a model 200, about 30+ years old, rebuilt by a reputable shop. The original Schwander action had new Renner whippens. The hammers were Renner blues, the bass strings probably Mapes. While overall the work was of reputable quality, it was a long way from Bosendorfer and had this strange burnt orange, thick lumpy finish on the plate.
The real question is, what is it? I would argue that it is not a Bosendorfer anymore since so many of the parts were not original. This flies in the face of common rebuilder philosphy, at least here in the US. This approach comes from the experience with American Steinway which says that a good rebuilder can actually make a piano BETTER than the original.
The issue is that assumptions made about one make of piano do not translate directly to another and most of the tweaks that people would take for granted in a Steinway actually deteriorates a Bosendorfer. If you own one, you can do with it what you want and there are some great high end technicians out there. You could done one of those wild bridge modifications, change hammers, Stanwoodize the action, add brass weights to the soundboard…LOTS OF STUFF, but I don’t know that you would end up with a better piano. Different, yes.
I’ve been trying to think of a proper analogy to keep from sounding like some corporate stooge and maybe here is one:
A major overhaul of a Bosendorfer by a high end tech, using some of the modifications above, is sort of like a sommelier choosing to take 3 expensive bottles of wine and blending them himself just before serving. Yes, the end result might be better than any of the 3 individual bottles, but many people want to see what the vinyard bottled, what the vinyard was looking for. They’re looking for the experience the maker intended, not what somebody else, skilled though they might be, thinks is right, just because he (or she) can.
These modification tools are great for helping older instruments, or ones that clearly have dificiences in important areas. This kind of modification is a relative recent development in this business. But doing so has ramifications.