The BMW M4 CSL is the Bavarian automaker's worst kept secret, but you get the feeling that BMW likes it that way. The CSL name is truly iconic for BMW, and it will have to pull out all the stops to ensure that it lives up to the original E46 M3 CSL. Fortunately, it appears that BMW isn't taking the task lightly and has released a new video to show that the car is being engineered to be the best it can be in every scenario.

As part of that, BMW announced that it is fitting the new sports car with Michelin Pilot Sport Cup 2 R tires. We didn't really need that info, as new spy shots have hit our inbox and provide even more details on the first-ever M4 CSL.

Back in January, we got our first glimpse of the lightweight seats that will be fitted to the new variant of the BMW M4, but now we get a properly clear view of these carbon-clad perches. They look amazing, and the fact that BMW's test engineers are willing to allow us to get close-up photos of the cabin confirms that the reveal of the most special M4 yet is certainly around the corner. As you would expect in a hardcore car such as this, the center armrest has been deleted and the transmission tunnel is almost totally covered in carbon fiber. A new steering wheel trimmed in Alcantara and featuring a center marker is also evident.

A production-spec version of the car was also spotted alongside its E46 CSL forebear, with this M4 CSL apparently finished in BMW Individual Chalk. The special wheels show off their special roundel for the 50th anniversary of BMW M, and the front splitter (again made of carbon fiber) gets an M4 CSL decal. An unveiling is clearly imminent, and the car looks like it'll be worth the wait, but beyond its styling, the above video from BMW M also hints that we can look forward to a Nurburgring record attempt. We've seen evidence to support such a theory, but we'll have to wait until later this month when we expect the car to be revealed along with a new Nurburgring video.