1.) Edsel

People said the same thing about the fuel restrictions under Group C rules, but it created some of the best and varied engines and cars until it was discarded for the sake of F1.

Group B was not just for rally cars. It was a regulation set with the main policy being homologation of 200 cars from a manufacturer (plus a dozen specials). The GTO was meant for sports car racing but the rules were changed before the racing series got off the ground.

The one that sets up the whole movie is the first moment, though, is when Doc Brown says "The way I see it, if you're gonna build a time machine into a car, why not do it with some style?" And the DeLorean rolls out of the trailer like some kind of modern Frankenstein's monster.

From the article:

Floating around on the net is Yamamoto's book, Rotary Engine, which addresses the issues Mazda went through.