The M4 CS turns heads, but 99% of the visual changes are driven by functionality rather than aesthetics. At the front there’s a model-specific front splitter, featuring exposed carbon fibre, which reduces front axle lift. The bonnet is made of CFRP (carbon fibre reinforced polymer) as is the recessed roof. These items save a little more weight and the case of the roof also usefully lower the centre of gravity. The spoiler on the rear of the BMW M4 CS has a Gurney flap – a small 90% tab on the trailing edge of the spoiler – in exposed carbon-fibre. It reduces rear-axle lift to optimise driving behaviour, particularly at higher speeds. The rear lights are shared with the big brother GTS and feature futuristic OLED technology, treating following motorists to a free dynamic light show with 3D effects every time you hit the brakes. Underneath them another shared GTS component, the M diffuser, is also made of carbon-fibre reinforced plastic (CFRP).


Inside, there are M4 CS treadplates to remind you that you’re about to drive off in something special. The seats, like the centre console are lightweight, and are upholstered in Merino leather and Alcantara. Even the door inners are lightweight, doing away with the stowage compartments, and you close the door by means of a lightweight M-striped fabric loop. Cute.


In power and torque the M4 CS is closer to the standard M4 than it is to the 500hp GTS. It develops 460HP and 600Nm of torque, accelerates the CS from 0-62mph in 3.9 seconds and on to a limited top speed of 155mph. But that’s not the only difference. The M4 CS also has Adaptive M suspension specifically tuned for this model, with Active M differential, M double-clutch transmission and a choice of three driving modes.At the limit it feels even more planted and eager to turn in than the standard M4, though you many need to be a track-day regular to spot the difference. Transmission is a seven-speed M Double Clutch Transmission with Drivelogic, programmed for extremely fast gear changes with no interruption in tractive force. The ten-spoke light-alloy wheels in Orbit Grey were specially designed for the BMW M4 CS and are based on the DTM racer; they’re shod with Michelin Pilot Sport Cup 2 tyres, 19-inch at the front and 20-inch at the rear.


Lightweight the interior may be, but it’s not spartan. Standard tech features include single-zone aircon, M instrument cluster, BMW Professional Multimedia including navigation and real-time traffic information, Bluetooth phone preparation, and an 8.8” colour display screen. Park distance control front and rear is standard. The audio system is exclusive to the CS (no speakers in those lightweight doors) and you can even download the BMW M laptimer app to show data such as speed, longitudinal and lateral acceleration and lap times on the Control Display.