My Brother recently saw at close hand one of these Jaguar "reborn" cars and says the detail isn't that sharp. (he owns an Etype resto company)
So the upshot is, there are companies out there doing as good a job and sometimes better though they won't hold the same weight I guess
As for a resto at 50k-100k I would concur that this is not possible if the work is carried out by a reputable company and is stripped back to every nut and bolt.
I did mine myself and that owed me 75k inc the donor which was 14k back when you could get them for that
