Other experimental features included multi-link rear suspension, gull-wing doors and a luxurious interior with leather trim and air conditioning.

The car used a fiberglass body shell and with a mid-mounted three-rotor direct fuel injected Wankel engine (code named M950F).

[2] The C111 III prototype that was completed in 1978, had a more aerodynamic bodywork that gave it an air drag coefficient of 0.195.

It had a modified 3-litre version of the Mercedes-Benz OM 617 five-cylinder Diesel, now producing 170 kW (228 hp), and a BMEP of 1.68 MPa, resulting in a maximum torque of 401 N·m at 3600 min−1.

[3] This set another record at the Nardò Ring in 1979, with an average speed of 403.78 km/h (250.958 mph), driven by Hans Liebold.