The CS stood for Coupe Sport or Sport Coupe. The 2800 CS and subsequent models featured a new front end that would influence BMW design for many years. The style of the C-pillar with the Roundel logos are unique to the CS models.

The 2800CS had the new 170 hp 2.8-liter single overhead cam (SOHC) six-cylinder engine designed by Alex von Falkenhausen. Although the four-door models like the 2500 and 2800 used rear disc brakes, the new 2800CS had rear drum brakes. The new CS was available with a four-speed manual or a three-speed ZF automatic transmission. The automatic was not well-received by the press, and it was soon replaced.

The rear seats. 

The interior was very richly appointed, with special contour rear seats. This design would be continued with the later 6 Series and 8 Series models.

The new body style marked the beginning of the E9 models. 

In 1971, BMW upgraded the 2800CS with a three-liter SOHC six and four wheel vented disc brakes. The new model was the 180 horsepower 3.0CS.