24. Citroen SM
Citroen wanted to enter the GT market in the early ‘70s, so they designed an elegant two-door coupe they named the SM. It had all the signature Citroen technology, but it didn’t have a proper engine. So, Citroen asked Maserati for help and the Italians delivered a 2.7-liter V6 engine.

It gave the SM a decent performance and some exclusivity; however, it lacked the reliability and dependability GT buyers wanted.