The Mid lives! I didn't take any photos of it along the way, because I wanted to enjoy it instead of documenting it. But here's how it sits now:
I've nicknamed it "Smokey," because the box and all its contents still smell like stale cigarettes, no matter how long I try to air them out.
I tore it down completely, cleaned everything up, straightened some aluminum parts (the chassis had front kick DOWN), and reassembled it with stainless steel screws. A pair of scruffy Turbo Optima wheels and some new Tamiya spike tires complete the rolling stock, and it's powered by a LeMans 360ST motor (keeping it in the family).
I'm having a bit of trouble with the steering linkage; it turns much more sharply to the left than to the right. Everything is centered and on straight, but the bellcranks are a bit worn. Not sure if that's the cause, or if the servo is on its way out (it's just an old Futaba S148). Other than that, however, it runs and drives great. I see why these were such prized race cars in their day; it just goes where you point it, as fast as you want it to go.
Now onto the body... it's original, unpainted, but very scuffed up from banging around in a box for who know how many years. I'll do it up box-art, and later, if I want a pristine shiny one, I'll get a repro.