Official: BMW M reveals the secret CSLs you’ve never seen before

Ever since BMW’s M Division started business back in 1972, only three cars have ever officially worn the ‘CSL’ moniker. The original 3.0 CSL everyone of a certain age gets gooey over, the E46-generation M3 CSL that warms the dark heart of the internet, and the latest M4 CSL.

However, there were four secret CSL prototypes that never saw the light of a Munich day, at least until now. Now, BMW M has revealed the CSL cars that never made it, and one of them – on paper – sounds like the most outrageous road-going M car that was never built.

So allow us to welcome in the M car you always wanted: the E46 you see above. “But M already did one of those CSLs,” you cry. Yes, but not one like this. Because this – “a crazy experiment” – packs the V8 from the E39-gen M5 – probably the most lusted-after M5 – which means 400bhp from that 5.0-litre eight-cylinder. “The entertainment value is high,” BMW M noted, hilariously.

Speaking of M5s, M did one of those as a CSL too. It’s the E60 saloon that looks like an advert for M, or maybe a sponsor car. Apparently this monster upped the 5.0-litre V10’s capacity to 5.7-litres, and in the process made it sound like an old Formula One car. It revs to 9,000rpm for goodness sake.

This monster M5 benefitted from a power boost to around 621bhp, and is matched to a twin-clutch gearbox, and had around 150kg of weight stripped from its bulk.

Its production sister car – the E63 M6 you see above – isn’t just the coupe version of the saloon, mind. Yes, it offers the same uprated engine as the M5 CSL prototype, same twin-clutcher and 100kg stripped out. But where it differs is with the addition of some active aero: a moveable front splitter and active rear wing for better airflow. There are also aero-friendly wing mirrors too. It’s “very, very stable” at speed, according to BMW.

Finally, BMW revealed the F87 prototype M2 CSL, which featured elements from the M4 GTS and got an uprated engine kicking out 444bhp, bucket seats, a rollover bar, a carbon rear wing and carbon ceramic brakes.

Have a watch of the video above. And no, you’re searching for ‘E46 M3 V8 engine swaps’….