Which Pantera model from "investment" point of view?

With 19 years of dreams and research from time to time I am now finally living in the US and ready to buy a Pantera.

Having owned an older AC Cobra replica for 4 years in the UK I know how much money sinks in to a passion for old special cars so this time around I would like go for a car that holds the value better.

I suppose it is a good start that they are not building anymore of them but within the production series of all special cars there are always models that generate more passion than others and so the big question I open up for is:

"Which model(s) are most likely to hold/increase it's value on a long term (presenting to be a better Return on Investment?"

I would like to expand on the question with the dimension of having different budgets:

Models that can be acquired in the $40K price area.

Models that can be acquired in the $50K price area.

Models that can be acquired in the $60K price area.

So let's open up with a comparison example:
Will a 1985 factory GT5 be a better investment than a 197X GT5 conversion?

I assume these 2 cars will be in different price brackets but from a Return on Investment point of view they can be compared at the point of resale as to how much value (in percent) they have increased/decreased and returned to the owner.

Thanks for your input.

Jesper