Could this be the rumored BMW M2 GTS/CSL?

A prototype of a hardcore BMW M2 has recently been spied close to the company’s testing facility in Nurburg, Germany, suggesting we will finally see a new addition to the sports car range very soon. The mule’s front end is still covered in heavy camouflage, but it's not enough to hide the significantly more aggressive fascia with larger air intakes in the bumper. At the back, there’s a massive fixed rear wing.

Update:

All those aerodynamic details are specific to the track-focused GTS versions, but the M2 might end up wearing the CSL moniker. The “top-of-the-line track tool, made on the track for the track” is rumored to receive a massaged 3.0-liter turbocharged engine with peak power in the region of 450 horsepower (336 kilowatts), making it by far the most powerful member of the 2 Series family.

Torque should be close to the M3/M4’s 406 pound-feet (550 Newton-meters). At this point it’s not clear whether the vehicle will use a six-speed manual gearbox or a seven-speed dual-clutch automatic

BMW M2 CSL Rendering

Inside the cabin, the track toy will feature a roll cage, M Performance steering wheel, and carbon fiber decorations. Alcantara-covered sports seats will complete the interior package. The range-topper will also get cup tires and coilover suspension, and might lose its rear seats.

According to a member of the German car forum 2ertalk, the M2 GTS/CSL will go into production in March 2019. It will be highly limited to only 1,000 units, all wearing a matching hefty price.

We expect to see more prototypes of the flagship M2 testing in the next couple of months, accompanied by additional technical details, so stay tuned.

Source: Tomedelic1 via BMW Blog