M6: Britain's oldest motorway. M6: BMW's newest car. We'll go for the latter, a car able (if electronic intervention is disabled) to run at just under three times the speed limit on the former but then BMW's M6 can also stop in around a third of the distances quoted in the Highway Code, so that seems fair.
Go figure, as they say.
Were such speeds to be felt in something like a 10-year-old Vauxhall Astra, you would surely be paddling in the breakers of insanity. It would feel all wrong and the sensory bombardment would probably blow a brain-fuse. But it's all about context, and a change in context can make even the paranormal seem normal.
The M6, the fastest car BMW has yet built, is essentially the five-litre V10 (with 10 throttle valves and fully variable valve timing) and the seven-speed sequential SMG transmission of an M5 transplanted into a BMW 6 Series coupe.
The result is a car lighter than the M5 and helped by plastic front wings and boot lid (as in the regular 6 Series) and a carbon-fibre roof (as in the CSL version of the M3) so it's even faster than that savage sedan.
Lightness, however, is relative; the M6 will deflect a weighbridge's scales to the tune of 1635kg. No wonder it needs so much power.
Power, yes - 380kW of it and the ability to spin the crankshaft at up to 8500rpm as 100km/h is dispatched in 4.5 seconds. The M5 needs the engine's manic ability to rev or it feels a little flat, but there's no such problem with the M6.
You can ease past slower cars while still in seventh gear, the rev-counter showing just 3000rpm. Flick down a few gears to double the engine speed and the thrust is almost explosive.
Then it starts to feel normal and not pyrotechnical. You even feel a touch disappointed if you press the Power button to toggle the engine back into its gentle mode, with a softer accelerator response and a scant 300kW. It makes the M6 easier in traffic, true, but it's pretty well-behaved anyway. I'll leave it at 380kW, thanks.
This is meant to be a kind of ultimate GT car but a strong competition car streak lies under its curiously alluring lines. The 6 Series was already the most understandable and most conventionally good-looking of all the Chris Bangle-era BMWs and the M-car treatment renders it fiercer without excess.
The wheels - huge 19" items - have five paired, slender spokes, and they are dished in such a way that a moving M6 seems to be hovering on four entrances to another dimension. How apposite.
If it has a racing streak, then a racetrack should reveal it. The test route takes us from Seville to the Ascari Race Resort near Ronda: its centrepiece, a sinuous test track. So far, I've been bonding with the BMW in a road context, nibbling at the edges of its abilities but not inclined to dive in lest the vast forces are irrecoverably deployed in an unfavourable direction.
Now, on the track, I can find out what it really can do.
Driver-configurable
Steering wheel-mounted M-Drive button pressed, of course. This is a short cut to a kind of all-in-one favourite setting, configurable by the driver. It can, for example, simultaneously select the firmest of three suspension settings - a stability and traction setting which allows more freedom before saving you from yourself, and number five out of six rising speeds of gearshift. Sounds about right for the track...
The revs rocket from a smooth-but-busy idle, the exhaust note changes from the double-harmonic boom of a five-cylinder Volvo (a V10 is effectively two straight fives) through a hard-edged blare to the raw shriek you'll hear from a V10 F1 car.
Then, a flashing on the auxiliary head-up instrument display signals the giddy rev limit.
Mein Gott! Pull the right-hand paddle back for second, then third, then aim over the crest and into a plunging left-hander. More fast bends, shift up, shift down to the tune of an automatic throttle-blip. Can the M6 really have so much grip?
The sticky Pirelli P-Zero Corsa tyres, related to those on the Maserati MC12 I recently drove, suggest it can. For a car so weighty to be so agile, so quickly able to marshal its forces to augment your own, is amazing.
Drifting beautifully
Brake hard for the hairpin and giant brakes do the job. Turn in hard, feel the steering pull at your hands in response, feel the tail bite, start to slither and bite again as the stability system intervenes. Actually, it might be more fun if that last bit hadn't happened, so I turn the system right off (which would not be so wise on a real road, especially a wet one).
Next lap, a spurt of power sends the tail drifting beautifully, just a little way but perfect for aiming into the next curve. It's smoother like that and lets you properly into the way the M6 reacts with the tar's topography.
And, in a powerful, heavy car, there's a lot of power assistance, even when the steering is tailored to feel quite weighty; the better to lean against when pressing on. Yet here is the M6 telegraphing a remarkable amount of information as to what's happening at the front wheels, just as a smaller, lighter car would.
It helps build an enormous feeling of confidence. So, I've edged over the other side of the M6's dynamic range and now I return to the fast, snaking road between Ronda and Seville, at one with the M6, even though spots of rain are triggering the automatic wipers.
I can experiment with ride settings, from firm-but-supple through to track-optimised and choppy, and I can overtake with precision and time to spare. No one minds; rather they are enthralled by the sight and sound.
Transmission refined
So am I. Is this the perfect four-seater (just) GT? Well, you could quibble: the SMG transmission can be abrupt on the first-second gearchange unless you set it to a gentler shift, but that's easily done with a button on the centre console. The permutations are many and add to the intrigue.
The SMG's automatic mode works quite well, too, and the whole transmission has been refined since the M5's launch last year, thanks to software updates.
Yes, a Porsche 911S is £15,000 cheaper than the M6's estimated £80 000 (UK sales start in the winter), and at £61 755, the M5 costs even less. That makes the M6 hard to justify, although it seems better value than a Mercedes-Benz SL55 AMG or an Aston Martin DB9.
But none has quite the same mix of appeals and attributes: a V10 engine in a slinky coupe, huge pace and the degree of fine control so dear to the keen driver.
It's a tough call, but the world is richer for the M6. - The Independent, London