The M35 was powered by a 49 bhp engine with a displacement of 497,5 cm3 (equivalent to 995 cm3) and was a 6CV under French tax rules. It had a top speed of 144 kph and was sold for FF14 000 - almost the price of an ID19 and more than double that of a 2CV.

A total of 873 GZ Birotors were built between 1973 and 1975. NSU employed the Wankel engine in the stunning Ro 80 with Rolls Royce and Mazda also investigating the engine's possibilities. It was rumoured that the CX would be fitted with this engine - indeed surprise was expressed at the time that the Birotor was not fitted to a top of the range model but to the mid range GS .
Powered by a rotary engine invented by Felix Wankel and built by Comobil, later Comotor, a joint venture between Citroën and NSU, the car was not without its problems - high fuel consumption, high pollution, high oil consumption and lack of reliability all served to kill the project. NSU was absorbed by Audi and the Wankel engine was dropped by European motor manufacturers.