BMW Z4 M Roadster

A tell-tale bulge in the bonnet and an aggressive front airdam distinguish it, while the trademark M Division four- pipe exhaust transmits the 3.3-litre straight-six engine's fabulous mechanical soundtrack into the cabin.

The Z4 is 85kg lighter than the M3, but has the same 343bhp engine, so performance is impressive. The six-speed manual gearbox has a short and accurate shift, while M branding features on the seats, wheel and gearlever.

As with the standard car, the cabin feels expensive, while the roof operates at the touch of a button. However, it's driving thrills that really matter in an M car, and to this end the suspension has been lowered and honed to cope with the extra power, while the M limited slip differential is used, too.

Grip and poise are impressive, while the ride only becomes harsh over really rough surfaces. The large engine up front means the Z4 squats at the rear under acceleration and can feel slightly nose-heavy, but it still manages to deliver a thoroughly thrilling drive.

And to increase steering feel, the standard car's electric power-steering is replaced by a hydraulic system. While the turn-in is super-sharp it still seems slightly artificial, but it can't detract from another job well done by the clever men from M Division.