BMW does not dole out the CS badge lightly, but when it does, the result is usually something pretty special – think of the 3200 CS Bertone of the 1960s and later the 3.0 CS in the 1970s.
More recently, the CS badge has found its way onto a few special M cars. It started with the E46 M3 CS and continued more recently with the latest M3 CS and M4 CS.
In these modern incarnations, the CS moniker usually denotes variants with enhanced power outputs and a bunch of carbon fibre body parts to ‘add lightness’. They are also usually offered in limited numbers, their exclusivity assuring fantastic value retention for their collectors.