The late Niki Lauda had three Formula 1 championships on his resume, but not every race car Lauda drove was a single-seater.

Part of an RM Sotheby's auction in St. Moritz, Switzerland, scheduled for Sept. 15, is this 1984 Mercedes-Benz 190 E 2.3-16, from the Race of Champions at the Nürburgring. The race was a one-off event held by Mercedes on May 12, 1984, to promote the opening of the track's new Grand Prix circuit. A collection of 20 notable drivers competed in a 12-lap race in identical cars.

1984 Mercedes-Benz 190 E 2.3-16 race car driven by Niki Lauda (photo via RM Sotheby's)

1984 Mercedes-Benz 190 E 2.3-16 race car driven by Niki Lauda (photo via RM Sotheby's)

Including Lauda, who who would win his third championship that year, the field boasted nine of the 12 F1 champions then living, plus future champions Alain Prost and Ayrton Senna.

The race also showcased the 190 E 2.3-16 sports sedan. It was a hotter version of the 190 E compact sedan designed for touring car racing, reinforced with a 16-valve inline-4 engine tuned by Cosworth. Race of Champions cars were modified by Mercedes-Benz Sport-Technik with a new exhaust system and suspension setup, 4.08 final drive, a bolt-in roll cage, a fire extinguisher, Recaro racing seats with 6-point harnesses, a quick release hood, a central circuit breaker, and wider wheels with Pirelli racing tires.

1984 Mercedes-Benz 190 E 2.3-16 race car driven by Niki Lauda (photo via RM Sotheby's)

1984 Mercedes-Benz 190 E 2.3-16 race car driven by Niki Lauda (photo via RM Sotheby's)

Lauda finished second in the race, 1.58 seconds behind Senna. Most of the 21 cars modified for the race were subsequently converted back into road cars and sold to dealers or brand VIPs, but the cars driven by Lauda and Senna were kept in racing spec. Senna's car went to the Mercedes-Benz Museum, making Lauda's the only Race of Champions 190 E in private hands. Lauda was reunited with the car in 2016, autographing its roof. The owner then had the car rebuilt by Mercedes-Benz Classic in 2017.

Previously offered for sale in 2018, The Lauda-driven 190 E is expected to sell for 400,000 to 500,000 Swiss francs, or about $450,000 to $565,000 at current exchange rates. That's a high price for an early 190 E 2.3-16, but likely cheaper than buying one of Lauda's old F1 cars.