That is a nice car, but I don't know if it will fetch 50k. Although, you never know with the value of the American dollar being as low as it is. Someone from Japan or Europe will show interest in it before someone from the states. Maybe he is just putting it out there to see if someone bites.
If I were to sell my car I would post it up for 30-40k. In my eyes it is worth every bit of that much. It could never be duplicated for 2x that price. I would never give it away but if someone wants to pay that much for it, bye bye. I was offered 26k for it 2 years ago and didn't take it. It would be in France right now if I accepted the offer.
As for sticking a Subi motor in it, I would rather cut the car in pieces with a sawzall and burn it before I would ever do something like that. :P :P :P