Sporting less camouflage back in September, our spies have spotted the track-oriented BMW M4 CS yet again. This time, it was seen testing in a rather unnatural environment for a performance car: snow. As seen here, the more aggressive M4 is currently undergoing extreme weather testing.

With the rest of the 4 Series lineup undergoing a facelift, it was only a matter of time before BMW also applied these changes to the M4. While still covered, expect a new pair redesigned headlight and tail lights. However, the M4 CS goes beyond these cosmetic updates.

Spied: Track-focused BMW M4 CS goes winter testing

In BMW speak, CS means Competition Sport and the package will also be offered in the four-door counterpart, the M3. It gets a unique trunklid reminiscent of the E46 M3 CLS plus a staggered set of alloy wheels. The hood is also different from the standard M3 and M4 with a more prominent 'power dome' and a single air outlet. Our spies say that the CS package also benefits from a few parts from the M4 GTS. These include the brakes, suspension and exhaust system.

The heavily camouflaged BMW M4 CS running in the snow

While notable changes were made to the underchassis and exterior, the interior only gets minor revisions. It is said that the interior will be upgraded with a new infotainment screen and some new controls on the dash. Also, expect the CS to come with its own seat and dashboard trims to separate it from the standard M3 and M4.

Rear quarter of the BMW M4 CS prototype

The BMW M3 and M4 CS will slot in between the the standard models and the track-ready GTS. Power ratings have yet to be mentioned but do expect it to be hit around with 450 to 460 PS mark as the GTS packs almost 500.