To a real Audi enthusiast that has the bucks, the Engine revamp and the cosmetic repairs for the purpose of enhancing the car, is not going to bother them, even enhance the appeal. However, to the "collectors" of this world, the car's originality has been compromised, and therefore it's value. It's a difficult one to call, but I'd buy it if I had a spare £26k lying around (which, unfortunately I don't)!
It's one of those car's that's "worth what it's worth" to whoever want's to buy it!