BMW M6

If you value posing as highly as performance, then the M6 cabrio is perfect – it certainly has that ‘bling’ factor. It is a fantastic driver’s car: the awesome engine note is matched only by the astonishing pace, while handling is impressively agile. But unless you crave wind-in-the-hair motoring, there is very little to justify the £4,600 premium it carries over its M6 Coupé stablemate.

If you’re in the market for a stylish and exclusive performance soft-top, then there’s no shortage of choice. Porsche, Lamborghini, Aston Martin – all promise to serve up open-air thrills... for a price.

But a new rival has appeared on the horizon, and with its V10 power-plant, the 507bhp BMW M6 Convertible could just pip them all to the post. With a 0-62mph sprint time of only 4.8 seconds, it nearly matches the M6 Coupé as the quickest offering in the BMW range – and at £86,400, it is the most expensive. No surprise, then, that the German manufacturer expects to sell an exclusive 150 a year in the UK.

However, next to its supercar competitors, it appears to be decent value for money. Compared to the likes of Lamborghini’s outlandish Gallardo Spyder, the styling is understated, but purposeful. Our test car was specified with white paintwork, which suits the lines well, but in a less striking colour (particularly silver) the M6 does not look as dramatic. At 4,871mm, it is more than 50mm longer than the usual 6-Series soft-top, due mainly to the rear airdam, while the flared wheel-arches provide a more muscular look. The unique alloys and four tailpipes are perhaps the most obvious clues to the car’s performance.

Inside, the interior remains unchan-ged from the M6 Coupé’s. The excellent seats provide plenty of lateral support, and although the red leather trim sported by our version may not be to everybody’s taste, the quality of the cabin is class-leading.

Yet this model is all about what’s under the bonnet – and it’s an awesome motor. The mighty V10 has huge thrust through the mid-range, with intoxicating acceleration – all complemented by a rumbling exhaust note.

In standard mode, the unit delivers 394bhp, but one press of the unassuming Power Button on the centre console boosts this to the full 507bhp, as well as sharpening throttle response. With no manual box option (something which, according to BMW bosses, is unlikely to change), the excellent SMG is the only transmission choice.

Mated with the Drivelogic system, it offers 11 individual shift options. This does seem over-complex, but in the sharpest of the six modes, each gear-change takes only 65 milliseconds, and the results are breathtaking.

Considering the car tips the scales at a hefty two tonnes (that’s 220kg more than the M6 Coupé, due to the roof mechanism), the performance is even more impressive. The dynamics have been tweaked, with a stiffened front sub-frame, additional rear strengthening and tuned suspension bushes.

The result is a machine which feels light and nimble, with good body control through corners. In fact, apart from the wind in your hair, there is no notice-able difference in handling compared to the Coupé; the loss of the carbon fibre roof hasn’t noticeably weakened the chassis. The soft-top itself takes only 25 seconds to drop, and when it is down there is very little buffeting in the cabin, even at motorway speeds. With such a limited number of cars available, BMW will certainly have no shortage of potential customers; there is already an eight-month waiting list. But, at £86,400, the M6 Convertible remains an expensive luxury.