$20,000 sounds really excessive. I've done business with a big shop in Dallas called Details, Inc., reputed to be the best in town for non-custom work. Everyone I know who's used them, including me, has been kind of stunned by their attention to detail. I asked for a (non-binding) quote on my '83 and he said around $5,000, down to bare metal, Mercedes paint, etc. That assumed no significant body work, and he said there were often big surprises under molding and other hidden places that trap moisture (which would be especially true in MA, I imagine.) $5,000 seemed awfully low to me, but it didn't seem like a come-on, because he was telling me I really should take it to one of those super custom shops. (I think he was afraid I'd be too perfectionistic.) He said the place he was talking about would probably be around $10,000.