BMW has been snapped testing what appears to be a more focused M5 'CS' on the Nurburgring.
Although it's very similar to the 'regular' M5 visually, there are a few hints this car is packing an extra punch. For one, it's wearing a carbon gurney flap on the boot lid, something BMW fitted to the M3 and M4 CS variants released last year.
There are carbon-ceramic brakes hiding behind those wheels, too, which was a calling card of the smaller M3/4 CS twins. Rumours have been swirling about a proper CS variant to sit about the M5 Competition for a while now, given BMW M has been rolling that model structure across its range recently.
Beyond the carbon rear wing and carbon brakes, though, there's not much separating the test mule snapped in Germany from the regular M5. That suggests this could simply be a tester for a new M Performance accessory.
It's not as if the standard car is slow, with 460kW on tap from its 4.4-litre twin-turbo V8 engine. It'll hit 100km/h in 3.3 seconds, on its way to a top speed that, with the limiter removed, is north of 300km/h.
With a fancy M xDrive system, you're able to rely on all-wheel drive for day-to-day traction, or disconnect the front driveshaft entirely and hang the tail out.
Stay tuned for more on the M5 CS on CarAdvice, and click here for more images.