In for a penny, in for a pound seemed to be Citroën’s mantra in the early ‘70s. If the act of producing advanced cars for bread-and-butter money wasn’t enough, the company decided that Wankel engines were its future. A twin-rotor power unit was first shown in the M35, but the project really bore fruit when Citroën installed the unit in the GS in 1973. However, it was too expensive and thirsty, and failed to sell. Within months of Peugeot’s takeover, the car was withdrawn and the company attempted to buy back all 847 cars back to save face. A few survive.