Back in the spring we managed to secure a BMW M5 for a cross Europe blast that culminated in a few laps of the Nurburgring. At the time we felt truly lucky to have experienced such a thing, perhaps a once in a lifetime chance to properly drive such a car. But then one quiet afternoon the phone rang and our friends at BMW offered up the car you see here, the new M6. As calmly as possible we thanked them, cancelled appointments and began ticking off the days. Our previous encounter with a big M car was mainly on the motorway on The Continent with very few excursions on back roads; the M6 would be subjected to a very different type of challenge. We decided to head north to the wide open windswept moor lands of Northern Scotland.

Nestled in the heavily sculpted nose of the M6 is the same V10, packing over 500bhp and with torque aplenty. On the road the effect is predictable: huge pace allied to fantastic flexibility. Six months after our trip in the M5 the M6 feels shockingly urgent. Time away from such propulsive force dulls the memory but the M6 definitely feels a little quicker than the saloon and sounds it as well: a bit of induction and exhaust fine tuning methinks. On a dry Nurburgring in May 507bhp began to feel insufficient; on the cold, wet, salted roads here in the UK in November let me tell you it feels more than enough. As you'd expect, the limiting factor is traction, on slippery roads the traction control light will still flicker in fourth gear. Whilst outright pace is compromised one can refocus concentrative powers on deploying the power smoothly and the challenge of doing so when exiting tight corner after tight corner without troubling the traction control.

Not having enough traction to utilise the lower gears is not a hindrance, as the V10's reserves of grunt are such that overtaking is more of an extension of thought than a physical exertion. Times and distances have to be recalculated to allow for the accelerative urge available and one never, but never, gets tired of the comedy value of depressing the Power button during hard acceleration and feeling the extra 25% of power kick you in the back. On the long, sweeping Loch-side roads in Scotland the novelty value of the power along with the glorious song being echoed off the valley side never wears. The same paddle shift SMG as the M5 allows the perfect interaction between gears and engine, and the perfect throttle blip on the downshift remains one of my favourite automotive treats, along with the beautiful growl that accompanies it.

Since our last meeting this V10 has won a number of accolades, including engine of the year. In all honesty it is probably better than that, one of the best of all time. Indeed when asked recently to form a list of the cars powered by the best ever engines I listed it twice - in both M5 and M6 guises. It's a triumph of technology: here is an engine that produces in excess of 100bhp per litre from a V10 that revs to 8250rpm with not a hint of vibration, whilst emitting glorious noise, and yet will hum away all but silently when you're not at play and return 25mpg at a motorway cruise. Ten years ago this would have been deemed a miracle. Now, it's here, in a relatively mass-produced car and backed up with a warranty and requires nothing but routine servicing and pump fuel. Incredible.

The interior is as opulent as you'd expect but is strangely devalued by the excellence of lesser cars' interiors now; the BMW Z4 shares some of the same switchgear for example. I'm not sure what to expect of an £80k car interior these days, as there is only so much a manufacturer can add in with the increase in price. Here there is I-drive, electric everything, a monster stereo system and more gadgets than you can shake a stick at. The Six offers acceptable accommodation for four adults; it's as roomy as the external dimensions suggest and also as comfortable, if not as voluminous as the 5-series.

The front seats are electrically adjustable with memory presets as you'd expect and offer excellent comfort as well as the support needed in a performance car of this ilk. The optional leather is great; it lifts what would otherwise be an overly dark interior and the quality, fit and finish is what you'd expect of a £5k option - I actually think it is worth the money. Throughout our test car's cabin the red leather was complemented by carbon fibre trim on the dash and doors, which is an acquired taste one must admit but I loved it as I'm a bit of a carbon fibre fetishist.

This is a happy coincidence as I can indulge myself with the M6. The entire roof is made of carbon fibre and it looks very, very cool. You can also while away a few moments looking for it elsewhere - it peaks through the grille, amongst other places, behind which it provides the support for the front spoiler. There was rumour of an M6 CSL but given the carbon fibre roof and other weight saving measures on the 'standard' car, I don't see where weight could be trimmed from easily. As it is, the mass has not only been reduced, but the centre of gravity has been lowered.

This pays dividends on the road. The M6 rolls less than the M5 and feels more alert and nimble. Without driving them back to back it is hard to be exacting in the differences but the M6 definitely feels like more of a focused sports car. It corners flat and fast with a wonderful balance and neutrality easily adjusted via throttle and communicative and well weighted helm alike. Given the bulk and size of this car, the agility and body control is incredible. The three different chassis settings allow fine tuning to the road in question with the softer setting catering for a typical British B-road, the firmer setting for A-roads and the hardest for very smooth road or track.

It's actually hard to believe how friendly the M6 is to push hard; it encourages you to do so by shrinking around you and being communicative and fun. On first acquaintance it is a little intimidating, but after a few miles and some time to adapt I found the M6 as easy to chuck about as a small hot hatch, just with much more potency. Grip levels are as extraordinary as you'd hope given the beautiful 19-inch diameter wheels shod with 255 section fronts and 285 rear tyres.

Behind the 5-spoke alloys nestle a huge set of stoppers that are faced with the task of reining in those 500 plus horses so intent on throwing the M6 at the horizon. Even after its diet the M6 is no lightweight and we found the brakes to have their hands somewhat full. I got to thinking that ceramic items may be a worthwhile option given the performance on tap. For the vast majority of the time the way the chassis and brakes contain the dynamic forces involved in driving an M6 at pace is admirable. My one real gripe, as this is a very personal one, is that I'd have preferred a broader brake pedal, or at least moved it further to the left. Given the wheel mounted shift and the ease with which one can pilot the M6 at pace I'd have liked to be able to use left foot braking without twisting in the driver's seat.

Overall, what we have here is a truly awesome car. On the one hand, a great GT in the traditional sense with mile munching capability coupled with comfort and refinement. On the other it's a great sportscar, harder edged and more raw than the BMW M5. Ultimately the value of the additional asking price will depend on the individual's specific needs. Adding the M6 to your stable (let's face it, most people who buy these will most likely already have several cars) is a question of taste. The looks still divide opinion like few others but it is indisputably individual. All will agree that the personality is a real winner and the relative scarcity and exclusivity will sway many in the favour of the M6 over the M5.

For me, the M6 faces some serious competition from Aston Martin and Porsche and I can't honestly say which one I would choose, as that decision would change from day to day. What I can say is that it would be lovely to have to make the choice in the first place.