We catch a close look at the M-cars that weren’t meant to be – and they are very, very special

BMW - BMW M Reveals Secret Projects Including A V8-Powered E46 M3 & An E60 M5 CSL - News

BMW fans, brace yourselves. For the first time ever, BMW M has given us a glimpse into its top-secret vault of prototype CSL machines – and there are some extraordinary machines here for you to ogle over.

Since BMW M Division’s inception in 1972, just three cars have worn the ‘Competition Sport Lightweight’ badge. First came the iconic 1975 E9 CSL, nicknamed the Batmobile. Then we saw the glorious E46 M3 CSL and more recently, the M4 CSL continued the lineage. BMW doesn’t throw this badge around lightly.

Check out the BMW M prototypes…

However, what we didn’t know was that BMW M has been working on a series of CSL prototypes over the years. These experimental machines have been locked away, kept out of the public eye, until now. Perhaps BMW M felt that we mere mortals weren’t ready for what it were capable of creating.

A new video showcasing these secret prototypes kicks off with a truly “crazy experiment,” in the words of Hans Rahn – Head of Vehicle Prototyping, Manufacturing Concept and Integration at BMW M. This incredible one-off E46 M3 CSL adopts the glorious 5.0-litre V8 engine from the celebrated E39 M5.

BMW - BMW M Reveals Secret Projects Including A V8-Powered E46 M3 & An E60 M5 CSL - News

The monstrous power unit has been tightly squeezed into the lightweight E46 M3 CSL engine bay and puts out 424bhp to the rear wheels through an ‘SMG’ sequential gearbox. Two enormous holes have been drilled into the car’s front bumper to help the eight-cylinder engine breathe, and the car produces a typically raspy soundtrack you’d expect from an E46, but with the deeper, more aggressive note thanks to those additional two cylinders. We love it, we want it, and we’d do anything to get our hands on it.

Next up is a prototype E60 M5 CSL with a racing-inspired livery. The prototype uses a bored-out version of the V10 from the standard car, upped from 5.0-litre displacement to 5.7-litres and now capable of singing its way to 9,000rpm while producing 621bhp. The E60 M5 has also had the typical CSL weight-reduction treatment, with some 150kg removed. Interestingly, it uses a prototype dual-clutch transmission instead of the original SMG.

BMW - BMW M Reveals Secret Projects Including A V8-Powered E46 M3 & An E60 M5 CSL - News

Last from part one of this special video series is a CSL version of the 2005 E63 M6. The car uses the same uprated V10 engine and twin-clutch gearbox from the E60 M5 prototype, while 100kg has also been stripped out. The M team has worked hard to improve the aerodynamics of this CSL, adding an active front splitter, an active rear wing, and aerodynamic “Doppelsteg” wing mirrors to improve stability while driving at high speeds.

See also: The New BMW M4 CSL Is A 542bhp Racing Machine With Flared Nostrils

BMW - BMW M Reveals Secret Projects Including A V8-Powered E46 M3 & An E60 M5 CSL - News

At the end of the video, BMW gives us a quick look at an F87 M2 CSL prototype, with an uprated 444 bhp engine, a carbon roof, carbon bucket seats, and an aggressive carbon fibre rear wing and carbon-ceramic brakes. Safe to say BMW M has been building some incredible machines behind the scenes. So, which of these prototype CSLs would you choose?