From the listing for this Porsche Racing 935 Car for sale:

Chassis 930 890 0016 was sold to Reinhold Joest who campaigned it in both the World Championship and the German DRM series in 1978. At Le Mans that year the car was sponsored by the Whittington Brothers, owners of the Road Atlanta circuit in America. They failed to finish and the car then resumed its DRM duties driven by Joest. At the end of the year at Hockenheim during practice, Joest crashed the car putting himself in hospital, the accident and effectively ending his driving career. Although damaged, the car was by no means a write-off.

From Wikipedia:

The Porsche 935 was a racing car made by German carmaker Porsche, introduced in 1976. As the factory racing version of the Porsche 911 turbo prepared for FIA-Group 5 rules, it was an evolution of the Porsche Carrera RSR 2.1 turbo prototype, the second place overall finisher in the 1974 24 Hours of Le Mans.

Beginning with the 1977 season, Porsche offered the 935 to customers entering the World Championship for Makes, in the IMSA GT Championship and in the German Deutsche Rennsport Meisterschaft (DRM). The 935 went on to win the 1979 24 Hours of Le Mans overall, and other major endurance races, including Sebring, Daytona, and the 1000 km Nürburgring. Of the 370[1] races it was entered, it won 123