Buy This Group 5 BMW 3-Series, the Most Radical E21 Ever Built

In the late 70s, Group 5 was the most exciting place in sports car racing. Wide open regulations allowed purpose-built race cars like the Ferrari 512 BB LM and Porsche 935 flourished, growing more extreme by the year. Those open regulations allowed for a wide variety of base cars to compete head-to-head, leading BMW to build a wild silhouette racer in the image of the earliest-ever 3-Series. These racers were the predecessors of the DTM cars of the 2000s, right down to a racing-only four-cylinder engine producing relatively massive horsepower. Today, one of them is available for sale.

This car, chassis R1-06, has almost nothing in common with a road-going E21 3-Series. While the roofline and a few body panels match the production car, the racing variant is built entirely around proven racing technology. The 2.0-liter M12/7 engine is from a Formula 2 car, revving to 10,000 RPM and producing a reported 330 horsepower. Suspension components come from the existing 3.0 CSL "Batmobile" racers, which also provided the blueprints for the extreme aerodynamic components.

This particular car was raced in the DRM, the predecessor to today's DTM, by Harald Grohls in the 1977 season. It then served as a show car at a BMW dealer for years before being sold at auction in 2002, restored starting in 2008, and listed for sale again this year. It is now available as a private sale, where RM Sotheby's lists the price as "available upon request."

You Might Also Like

• You Need a Torque Wrench in Your Toolbox

• Tested: Best Car Interior Cleaners

• The Man Who Signs Every Car