Damn shame we'll never have an answer.
When it launched in 1989, it seemed to make complete sense for BMW to give its new 8 Series the M treatment. Sadly, it didn’t happen. In fact, BMW engineers claimed at the time that the big coupe was simply too heavy for an M badge. But as many already know, that wasn’t entirely true; an M8 prototype was made but never received production approval. Why? The typical scenario of when corporate accountants won the argument. So what did we miss out on then? Try a 5.0-liter V12 with 550 hp, for starters.
Exact performance figures were never given, but many believe a 0-62 mph time of about 4 seconds is about right. All of that power was sent to the rear wheels via a six-speed manual and a limited slip differential. And in a sign of the times to come, the prototype made use of lots of carbon fiber to shave off unnecessary pounds. Even the interior was stripped out, with Alcantara racing seats using four-point safety harnesses instead of the familiar leather. Various other structural changes were made for improved rigidity and the front grille was redesigned for better air flow. Would the M8 have been an instant classic, a BMW supercar to succeed the legendary M1? Sadly we’ll never know and it’s a shame BMW didn’t make this one happen.