BMW has unveiled the ultimate version of the 6-series and the latest car to wear the prestigious M badge.

The M6 will follow the launch of the M5 in the UK and uses some of the lightweight design features of the M3 CSL.

It features a 5.0-litre V10 engine producing 507bhp and comes with a programmable seven-speed sequential manual transmission (SMG). Its lightweight body panels include a carbon fibre roof and it will accelerate from 0-62mph in 4.6 seconds with top speed restricted to 155mph, although it is claimed it would be capable of more than 200mph derestricted.

Powered by the same engine as in the M5, the M6 develops maximum power at 7,750rpm with the red line set at 8,250, while maximum torque of 384lb-ft is reached at 6,100rpm. Fuel consumption is 19mpg on the combined cycle with carbon dioxide emissions of 357 g/km. It also features the M version of BMW’s head up display (HUD), which contains information on engine speed and gear-shift warning, which is projected on to the windscreen on the driver’s eye-line.

BMW hopes to launch a diesel version of the 6-series in 2006 and is putting together a business case before the plan is approved. The company believes there would be sufficient demand from corporate customers who run diesel-only fleets. The proposal involves using the twin-turbo 3.0-litre six-cylinder engine offered in the 535d, which produces 272bhp and 413lb-ft, combined with a six-speed automatic transmission.

In the 5-series, the engine is capable of 35mpg on the combined cycle with CO2 emissions of 211g/km. If approved, the car should go on sale in 2006.