When it comes to cars, the letters B, M, and W carry huge credibility. But the extra letters and numbers that follow make all the difference.

A second M for example, means the hot rodders in the Munich maker's performance and racing skunkworks have played with everything from the drivetrain, aero and suspension, to the rims, rubber and interior design.

The number sitting next to it then determines whether you're looking at a compact firecracker (M2), fast-lane monster (M5), or bruising family truckster (X6 M). But every now and then some additional letters find their way onto even a BMW M car's bootlid.

In this case, a C and an S are significant additions to the already impressive M4 badge. They stand for Coupe Sport and were famously applied to BMW's achingly beautiful (E9) coupes of the late 1960s and early '70s.

So, with the howling echo of that all-time classic's in-line six ringing in its ears, the new M4 CS stands up as a proper high-performance coupe, pitched against the likes of Audi's recently reborn RS 5, the Lexus RC F, and Merc-AMG's soon-to-arrive C 63 S Coupe.

Does the CS legend live? Read on to find out.