While StevieB has some valid points, that doesn't mean you can't do it your way.
To my eyes, a late model corvette may be the best place to start getting the general shape of the concept car and then graft on the shapes and elements that make it recognizable as the concept car.
And you may find that you may need to just put all the parts into a box and save this project for later.
this link has wheels that accept various wheel design inserts:
https://slotcarcorner.com/1-32-Slot-Car-Parts-by-Type-/Wheels-and-Inserts/CB-Design/Insert-Wheels-15x8mm-Silver-p2223.html
I think most of the body is close enough to rework, the rear window would most likely be easier to fix than the work required to create the front and rear bumper and facias, I guess this will remain on my far back burner.
Randy, those look great and there is surely a market for those.
I was thinking more of deep-dish model-A wire wheels similar to what monogram put in their '30 woody, or kelsey-hayes style suitable for caddy, t-bird, chrysler
looks pretty "silky" to me, since I know exactly what you had to work with. I think I've finally spotted why this body looks so "disproportionate", the doors are too short for a two door sedan (and of course, the front of the car is too flat).
Try searching the Mechwarrior universe for the Rifleman. (personally, I prefer the Marauder over the Rifleman)
I encountered mechs back in the 80's through the first Mechwarrior game (which would run on a "286" based PC. Battletech has been around for longer than Mechwarrior (the computer game) and has a large audience, there is a free online version of Mechwarrior that has very good looking graphics.
I have a few "gundams" because of the mechwarrior game but they are over 30 years old at this point and I never finished one yet ( I also have mint unbuilt star wars R2D2 and C3PO ).