When you have been into very many pieces of gear, you begin to see what sacrifices are made in production to shave costs. A good example would be RFI suppression and even underrated components. I suppose the purists would want to maintain and even document all of the OEM flaws. It has often been stated at the Antiques Roadshow, never to have repairs done as it destroys the historical ambiance of the piece.
This is doubly true with electronics, where even new original parts have crumbled to dust in the original boxes. I can't imagine anyone doing most all the mods you described, but finding original parts in good order could drive up the delivery time and price immensely. In this country, the ac cord would probably have to be changed for safety reasons. You would want to specify to the repairman up front that he might not be paid for a very long time while he conducts considerable research in order to find the originals. But if money is no object, perhaps an open account or a blank check up front would be in order. The absolutely professional repairman these days would tell you it's burned out and the parts are no longer available and steer you to the showroom for the latest cheesy junk.