I don't see the point of this. If you want a Z, get a Z, if you want a Fiat 124, get a Fiat 124. You have two completely different body styles, one old, one new, at best, this is going to look like a cobbled together franken-car. I generally find that new parts stick out like a sore thumb on old cars, and vice versa. You'd be better off getting an MX5 RF, and doing something custom with that than trying to make a Z part fit, or just getting a regular MX5 and doing a custom hard top. You could take molds from a Z and make a fiberglass hardtop based off of that if you wanted, but cutting up a Z and trying to put the steel roof section on the roadster is a bad idea, and will result in one less Z available.