Lotus Carlton, that was a special saloon!
That Rover 220 was supposed to be a very quick car, but all the reviews of the time said the chassis couldn't handle all that power.
The turbos are the weak spot of the Maserati 3200, apparently they do fail and they cost a lot of money to fix. The rear exhaust silencers also cost silly money, there's rust problems too so that's why many just skip it and go for the 4200. 4200 with boomerangs... I like the sound of that!
As for the definition of a supercar, I think it has to be a full on, low-slung sports car, not a coupe or saloon, look amazing, be rare and of course cost so much only the few can afford it. Oh, and have a huge top speed!
Ex '99 6-speed 3.0 V6 GTV, now Z4MC