Darin - reading that you refuse to add a top to the car was painful to read.
A top could be made to come right off with just a few bolts or something fancier that is quick release.
You could even make it out of canvas stretched over ribbing.
It would be for SCIENCE, man ! ( Lol )😛
I even started looking for a used one myself to modify.
Just a toy project I would keep at my parent's place.
I was thinking I could find one for like $1,200 , but then saw the insane prices the cars are fetching now.
I have seen several 1990 cars going for 12 -14 K !
It's funny that you called the car the same thing as what I did - I told my sister I was looking for a little 'turd bucket ' Miata.
So this is my dream :
Modify a Miata into something like a Panhard LM 64.
That drag coefficient was .12 - POINT TWELVE !
Even if off by several counts in reality, this is a car that has one of the best cD figures of all time on a side by side "real" car.
I realized that the upright fins actually have another purpose besides stability : safety.
The car is so low to the ground and the tail would pretty much be a ramp to a large SUV driving behind you.
( One of the reasons I gave up on the dream of creating a Karman Ghia streamliner )
Not only could the fins add a tiny bit of safety from behind ( If they had a strong steel bar inside ) but they would also make the car more visible in parking lots.
There is a fella that added a full boattail to Prius has had the problem of people wrecking into it because it is so low at the back. The fins could help this problem.
As a bonus, you could be amused at the people asking you if you drive a fake Superbird kit car.
(They would have no idea that the Superbird copied the LM64. )