The C9 was a development of Sauber's previous C8 design, retaining a monocoque that largely consisted of aluminium, although considerably stiffer and with numerous other improvements.

The rear suspension changed from vertically positioned spring/damper units arranged over the top of the gearbox to a horizontal layout aligned with the longitudinal axis of the car.

Aerodynamic changes included the repositioning of the combination of oil/water radiator to the nose of the car, which allowed the use of a modified splitter plate.

Aerodynamically, the car had two configurations: one for sprint circuits and a low drag version for the 5.8 kilometre Mulsanne Straight at Le Mans.

[4] For its debut season in 1987, the cars were run by Kouros Racing, named after the fragrance brand of its parent company, Yves Saint Laurent, although backed by Mercedes-Benz in a semi-official capacity.

This coincided with a change of senior management at Mercedes and the announcement in January by new deputy chairman Prof. Dr Werner Niefer that the company would support Group C sportscars.

[6] As a result, Mercedes was sponsored by AEG-Olympia – AEG being owned by Daimler-Benz at the time, effectively giving the team full factory support.

The car's speed potential was made clear when Johnny Dumfries set a lap record at Le Mans before retiring with gearbox failure.

Schlesser won the final race of the year, the non-championship Nurburgring Supercup, which was the only win in an otherwise bleak season for the Swiss-German team.

[9] The C9 won five races in the 1988 World Sportscar Championship, showing much-improved reliability and placing second in the overall standings behind the winning Silk Cut Jaguar team.

In the 1989 World Sportscar Championship, the Sauber C9 won all except the second race at Dijon Prenois, where they were defeated by the Joest Porsche 962 of Bob Wollek and Frank Jelinski.