In 1999, Audi surprised the world when it announced it had built two contenders for Le Mans. The engineers at Ingolstadt could not decide whether ACO rules favoured a roadster or a coupe, so they built one of each. The roadster went on to dominate sports car racing for several years. The R8C coupe failed to finish and the project was cancelled - or was it?

On behalf of BMW North America, the McLaren team prepared and ran a beefed up version of the BMW 320 in the IMSA series.

After withdrawing the Le Mans-winning V12 LMR prototype at the end of 2000, BMW tasked the Schnitzer tuning company to build an M3 that could take on the Porsche 911 GT3 in the American Le Mans series. As is so often the case in motor racing, success came by cleverly exploiting badly worded rules.

Over the years, BMW and their sporting partners have produced some of the most exciting racing machines and clothed them in evocative racing colours. The gallery presents a fine selection, including some of the famous BMW 'Art Cars'. Also included are the 3 series CSL, 320i and M3 GTR, the M1 variants and the IMSA GTP cars

The Dome RL and RL-80 were two of the most exotic sports prototypes that ever graced the Circuit de la Sarthe. They were built to promote the Japanese Dome Company's equally exotic Zero and P2 1970s supercars.

The Ford GT40 is one of the most famous racing cars ever built. Ford Motor Company developed the car at its Special Vehicle Operations factory in Slough, UK with one aim in mind - to beat Porsche and Ferrari at Le Mans. Most iconic of all were the twice victorious blue and orange 'Gulf spec' cars raced by the John Wyer organisation.

Designed by Pininfarina, built by Dallara and powered by an Abarth-tuned engine, the sleek, turbocharged racing version of the Lancia Beta Montecarlo was one of the finest track cars to come from Italy at the end of the 1970s.

The Stratos is rightly remembered as a spectacular world-conquering rally car. Less well-known is the highly modified Group 5 silhouette car that won the Giro D'Italia in 1976 and 1977. The database and gallery each contain a rare archive of photographs from both races.

Colin Chapman's Lotus 72 is the distinguished Grandfather of the modern F1 car. Clad in the black and gold colours of John Player, the 72s are true 1970s motorsport icons.

Most people remember the six-wheeled Tyrell Project 34 F1 car but this was not the only single-seater with more than four wheels. March Engineering in Bicester also built a six-wheeler. However, unlike the Tyrell, the 2-4-0 had four wheels at the rear. The 2-4-0 never won a race but by an odd twist of fate, it was the most profitable car March ever constructed.

In the 1960s, Can-Am was the most technically advanced racing series in the world. The racing was never that great but the technical regulations were virtually non-existent and included no upper limit on engine size or a minimum weight. Consequently, the hugely overblown cars looked and sounded glorious. The greatest of them all by a country mile were the 8 litre Chevrolet-powered powder orange McLarens.

McLaren never intended for its fantastic F1 road car to go racing but, when the world of sports car racing shifted away from prototypes towards production-based GT cars in the mid 1990s, the F1 took to the track and swept away the opposition.

German national motor racing has always produced a wonderful array of exotic machinery. In the 1990s, the DTM (Deutsche Tourenwagen Meisterschaft) was a hugely popular series and a hotbed of advanced motorsport technology. The AMG-built Mercedes C-Class was the car to beat.

When the DTM collapsed at the end of 1996, Mercedes Benz took a look at conventional touring car racing and decided it was not consistent with the high-tech image of the Stuttgart marque. Instead, they built an astounding GT car that made their competitors look like amateurs. But spectators at the 1999 Le Mans 24 hours might have a suspicion that sports car technology was being pushed too far...

By 1977, the 2 litre Porsche 935 had become so dominant in the separate Division 1 class races of the DRM that the press began to dismiss it as a boring, one-make series. When German TV refused to televise a Division 1 race at the Norisring circuit in July, Porsche ordered its competition department to build a special 1.4 litre 'Baby' 935 with the aim of winning the televised second division race�

Noticing a loophole in the FIA regulations that had been designed to give the front-engined BMWs a chance to compete in the upper division of Group 5, Porsche engineer Norbert Singer realised he could create a slippery new 935 that might out-run the prototype cars along the high-speed Mulsanne straight at Le Mans. The result was the radical 935/78, now fondly known as the 'Moby Dick'.

Although normally associated with BMW, the Schnitzer tuning company built a radical Group 5 version of the Toyota Celica Liftback for Harald Ertl to race in the DRM series.

Following the success of the Cologne Capris in the early 1970s, Ford contracted Zakspeed to build a Group 5 racing version of the Mark III Capri for the DRM. Dubbed the 'Wunderwagen' by the German motoring press, the glorious fire-spitting Zakspeed Capri is still an object of fascination for motor sport fans to this day.

Following success with the Ford Capri in Germany, Zakspeed built a silhouette version of the Mustang to compete in the American IMSA series. The racing Mustang was a thinly disguised re-skinning of the Gr5 Capri and was all the more fantastic for it!

Another Zakspeed creation, the bizarre but spectacular Group 5 version of the Lotus Europa.