BMW’S fastest production car, the M6, has arrived in Australia, hard on the heels of the M5 sedan to which it owes most of its mechanicals.

Powered by the same 412kW 4.4-litre twin turbo V8 at the heart of the M5 and equipped with an identical seven-speed dual-clutch transmission, the M6 has the dash to go with the flash.

Available in two-door Coupe and Convertible guises, the four-seat grand tourer can achieve 100km/h in just 4.2 seconds in its Coupe form – one tenth of a second faster than the M5 sedan.

Even the two-tonne M6 Convertible can hit highway speeds in just 4.3 seconds.

However, the M6 – based on the 6 Series launched in Australia about a year ago – costs a hefty $60,000 more than the 650i that comes with a less forceful 4.4-litre V8.

The question is whether punters should fork out the extra for the M-enhanced version …