And now here's a closer look at the only privately commissioned work in the BMW Art Car series.

It's auctioning alongside Sahib Bahadur of India's 1925 Rolls-Royce New Phantom, which you might remember is equipped with a cannon for hunting.

This Beemer, actually a 1979 BMW M1 sports racer, was painted by artist Frank Stella and originally owned by the late seven-time world champion IMSA racer Peter Gregg.

The car is one of 16 official Art Cars created for BMW to race in worldwide series, including the famous 24 Hours of LeMans.

Rolling work of art... The 1979 BMW M1 painted by artist Frank Stella

Other cars in the series were painted by the likes of Roy Lichtenstein, Robert Rauschenberg, Alexander Calder and Andy Warhol.

Jeff Koons also recently added his own contribution to this 'great racing art canon' (pictured below).

Yet the 1979 BMW M1 was the only privately commissioned example. Peter Gregg personally ordered the car from BMW Motorsport GmbH.

Stella then painted the car to resemble his "Polar Coordinates" series of artworks, in tribute to his and Gregg's mutual friend, Ronnie Peterson - making this car arguably more 'personal' than the others in BMW's series.

Peterson was killed in a Formula 1 crash in 1978.

BMW's Art Car series includes this recent design by Jeff Koons

Bonhams' presale estimate for the unique race car in $450,000 to $600,000. And it has provenance to match its significant valuation, having been in the possession of the Guggenheim Museum since 1999.

The sale takes place August 18 and 19. Paul Fraser Collectibles will bring you highlights when they become available.