I wouldn't pay 75K(or half that) for any Z3 rebody.
You ain't gonna get a 250 california, then, are you?
It would cost you £35k minimum to build one (if you can find a body now) to a decent standard.
They are not the same animal as any tribute automotive bodied cars. Sorry but it's true.
All 250 cali bodies are based on DNA's designs, which were very, very authentic to the original. The only reason they chose the Z3 as a 'base' is because it almost dimensionally correct to the original. That was their downfall. The Italians didn't like it because they were 'too good'.
The likes of 'Tribute' learned from DNA's problems, so make their bodies so as to not upset the original manufacturers (whoever that may be). So they are not at all authentic.
Therefore, the market for Tribute cars just isn't the same, no matter how well they have been built (or not).
I get a lot of people asking what my car is worth. A lot. I always tell them it's not a Ferrari and give a figure of 'around £80k'. I have never had anyone say it isn't worth that. Never.
I can't go anywhere in my car without many people either flashing their lights, hooting, pedestrians giving the thumbs up, people reaching for their phones, or shouting 'lovely car' in the street. If I stop anywhere, I ALWAYS get people approaching and asking about the car, or asking to take pictures, or both. Petrol stations are a nightmare, it takes ages to get away. This isn't me being arrogant, or showing off, it's just how people see my car.
So, if you like that, and the idea of owning a very pretty car which makes people happy, £80k is a small price to pay IMO.