First Drive: BMW M6 M6 2dr DCT

The harder they are, the more we like 'em, so when it comes to the M6 Convertible you can't help thinking that this is the BMW M car that has drifted as far from that template as the company will dare go.

On paper, this latest incarnation does its best to kill that suspicion stone dead. With the same mega 4.4-litre twin-turbo V8 under that chiselled nose as the one that turns the M5 into arguably the stealthiest Q car of all time, the M6 has 552bhp and more than 500lb ft of torques, ALL of which is funnelled to the road through the rear wheels from just 1500rpm. This is the flattest of torque curves.

It'll also hit 62mph in 4.3 seconds, would probably nudge 200mph if it wasn't limited to the usual 155 and, as is the modern way, somehow delivers more while using less fuel and coughing out fewer CO2s. In this case, averaging a claimed 27mpg and emitting 239g/km. On paper, then, largely irresistible.

Gallery: the new BMW M6 Coupe and Convertible

It looks pretty good, too, with a front apron that is clearly aiming for a vampiric effect, pumped wheelarches which lend extra visual muscle to the 30mm wider front track, extended sills, and a reprofiled rear with four exhausts. A little M6 badge also appears in the front grille for the first time since the original 1980s car. In frozen matt silver or deep blue, riding on either the standard 19in alloys or optional 20s, this is a car that doesn't wear its potential particularly lightly.

Yet it somehow doesn't quite gel on the road. You know the phrase, ‘the whole is greater than the sum of its parts'? Well the M6 convertible is a whole that is a little overwhelmed by the sheer number of parts that BMW has chucked at it. Especially the armoury of electronics that govern the way its chassis and transmission behaves.

To be honest, this is a car that Bill Gates and Mark Zuckerberg would struggle to get their heads round, given the sheer computer firepower it packs. Gearbox, (hydraulic) steering, suspension, throttle response, and traction control: there are almost 500 different combinations for the driver to choose from. Theoretically, this much choice can only be a good thing, right? Especially when your optimum set-up can then be stored in not one but two M buttons on the steering wheel?

Uh, no. Just as Spotify offers you the choice of about eleventy billion songs but most of us end up sticking to the stuff we know and love, so the M6 could benefit from a little judicious editing. All this choice smacks of marketing dazzle rather than focused engineering, and there's the lingering feeling that whatever set-up you settle for, there's probably a better one lurking underneath. To be honest, I'd trust the geniuses at M to work that out for me. The über-brilliant M3 GTS is a laser-focused example of that.

Not that the M6 convertible isn't a seductive car. That BMW chose to launch it in California is telling, and blasting roof-down through the mountains of So-Cal, revelling in the super-fast shifts of its DCT dual-shift 'box and surfing all that torque, is enough to confirm that this is one mighty thing. It also rides beautifully over lumpy surfaces, soaking up the worst that under-nourished Californian asphalt can throw at it, and it's seriously stiff too. It throws itself down the road with almost casual abandon, and hooks up long sweepers and short, stabbing corners with impressive nonchalance.

And, as I discovered when I carried way too much speed into one tight hairpin, the electronics will step in to cover for driver idiocy with breathtaking speed and effectiveness. It has grip to spare, and moves in a way that is close to galactically fast without really feeling like it. (It disguises its speed amazingly well. That's what I told the CHiP who pulled me over at one point, anyway.)

Even more than the M5, the M6 convertible is a car you admire rather more than you desire. It looks great roof up or down, goes like hell, has a beautifully made and well-appointed cabin, but the truth is this is a car with a Mensa-level IQ that lacks a bit of real-world magic.

There's also the small matter of its £99,000 cost. Really? That pitches it squarely against the awesomely fine new Porsche 911 cabrio, the new Merc SL500, the flawed but super-sexy Maserati Gran Cabrio, the Aston Vantage roadster, or the supercar-fast Jaguar XKR-S, not to mention a used low-mileage Audi R8 Spyder or even a higher mileage used Lamborghini Gallardo Spyder. That's not choice, that's war.