Earlier this year, we were very excited to report that the legendary CSL name may be returning for BMW M's 50th birthday. While there has been no confirmation on it whatsoever, spy shots of a modified M2 have suggested that BMW M's Coupe Sport Leightbau (lightweight construction) name may be given to its smallest car. But then we came across spy photos of a hardcore M4, and now it seems that the CSL name may well be affixed to the benchmark sports coupe that most expected. Based on these spy shots and some creative license on our part, we've rendered the M4 CSL below, but if the car is to become real, what can we expect?

Although not clearly visible in our render, spy shots have shown one of the M4's hardcore test vehicles sporting a chunky roll cage, much like the M4 GTS before them. Although BMW could make a case for a cage by removing the rear seats and other unnecessary equipment like the climate control, it's worth remembering that a proper roll cage is heavy, and that doesn't fit with the CSL approach. Nevertheless, whatever safety systems the car has, it would be produced in very limited numbers, likely up to a run of 1,000 units. If the CSL does come as an M4, expect it to be based on the "entry-level" Pure version of the current G82 style, with RWD and a manual gearbox.

To lure more buyers in, it would likely get a power bump over the Pure M4 and would possibly have some special upgrades too. In the last M4 GTS, we saw water injection used to boost performance, while the E92 GTS saw the fitment of a titanium exhaust. Thus, tomorrow's M4 CSL would likely have some unique performance enhancements, upgraded suspension, a lightweight exhaust system, and possibly even active aero. You can also bet on loads of carbon fiber throughout the car and plenty of Alcantara and suede in the cabin. Uncomfortable but grippy bucket seats are also likely, along with unique wheels and possibly even a special paint finish. We'll have to wait for next year to see if our guesses are right, but either way, this is a car BMW can't afford to get wrong.