Gallery: M celebrates its 40th birthday

But people don't remember the 3.0CSL for its lack of weight. They remember the way it looked.

The final 3.0CSLs to be homologated had a - now infamous - aero package. Thanks to a huge air dam, blades running down the front wings, and not one, but two, rear spoilers, it became known - unofficially - as BMW's ‘Batmobile'.

The 3.0CSL was M's first project, and they tinkered the race cars into absolute dominance. No mean feat for relative newbies. It was the most successful touring car of its era, winning the European Championship six times between 1973 and 1979, and sat astride the international touring car scene for almost a decade. Which made Jochen Neerpasch's splinter cell of speed a new force to be reckoned with...