BMW M8 Convertible

BMW never produced an 'M' version of the old 8 Series, so this M8 Competition Convertible represents a few firsts for the brand. Its customers have never before been able to go so fast with the roof down.

An incredible 616bhp and 750Nm sees to that, launching the drop-top from 0-62mph in just 3.3 seconds, despite it weighing well over two tonnes. Four-wheel drive helps it get smartly off the line, while an eight-speed automatic gearbox means you can simply keep your right foot planted and grip the steering wheel. It's also possible to disconnect drive to the front wheels, but this is best reserved for private tracks where the M8 will happily oblige with smokey skids.

There's a myriad of settings to adjust the driving experience and even the exhaust note, and they’re accessed via the touchscreen or a set of red 'M' toggles on the steering wheel that look like they've been borrowed from a fighter jet. The steering is precise and reactive, doing a good job of hiding the M8 Convertible's size, but a lack of feedback and masses of grip means it can be hard to feel the car's limits unless you take the car to a track. In other words, this is the polar opposite of an Mazda MX-5.

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Another area where the convertible M8 looks a little suspect is its price, coming in at a heady £130,000. That's for a car that feels similar inside, albeit slightly less comfortable, than the diesel version costing around £50,000 less - and which itself is hardly slow.

The M8 Convertible could be something of a last hurrah for BMW convertibles with thumping V8 petrol engines as emissions restrictions get stricter. Aside from stop and start, there are few compromises in the name of economy.

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As a result, the 4.4-litre engine can only manage 25.2mpg on the combined cycle, with CO2 emissions of 254g/km. Expect sports car running costs, then, with a road tax surcharge in the first five renewal years (for a total of £470 annually), pricey insurance premiums and high servicing bills. With so much power and a weight of over two tonnes, consumables like tyres and brakes aren't likely to last too long.

We already know its engine from the BMW M5 Competition but the familiarity doesn't diminish the sensation when you first put your foot down in the M8 Competition Convertible. The output of 616bhp gets this four-seat cabrio from 0-62mph in 3.3 seconds - just a tenth slower than the coupe and on a par with most supercars. Its acceleration only stops at the 155mph limited top speed, which can be extended to 189mph with the optional M Driver Package.

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It's a shame the exhaust note is rather muted, though, with even the BMW M235i sounding more boisterous, producing pops and cracks when you release the accelerator after a burst of power. The eight-speed automatic gearbox is usually very smooth but it can be hard to modulate at low speeds, and makes pulling away a balancing act between barely moving and rocketing off the line.

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In any of its driver settings the M8 feels sharper than the standard car, with firm suspension and direct steering that does a good job of hiding its weight at low to medium speeds. It can be hard to gauge just where the car's limits are, though, so it's best not to push too hard unless you're on a circuit. A Porsche 911 Cabriolet makes more sense if you're after a rewarding driver's car, as does a Ferrari Portofino if your budget can stretch to it.

The M8 occupies slightly tricky territory in the range because in most ways the 840d is just as comfortable and high-quality inside, but it costs a massive £50,000 less. Spend a little more than the M8 Convertible's asking price and you could buy a Bentley Continental GT Convertible, which has one of the best interiors on the market.

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Apart from the roof, which opens in just 15 seconds at speeds up to 31mph, the highlights are carbon-fibre trim, a new gearlever, an 'M' steering wheel and lovely sports seats embossed with the 'M8' logo. Standard equipment includes BMW's latest infotainment system with a 12.3-inch digital instrument display and 10.25-inch infotainment screen. You also get a head-up display with M-specific readouts so you can get vital information without taking your eyes off the road.

There aren't many luxury four-seat convertibles on the market, so your choices here are somewhat limited. The M8 is one of the more practical examples, with a 350-litre boot that should be adequate for at least a long weekend away. It's worth noting, however, that the boot opening is like a letterbox with the roof down, so it's better suited to squidgy bags rather than hard suitcases.

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We also noticed that the length of the M8 Convertible's open interior means things can get rather blustery, especially in the back. At higher speeds your passengers will definitely want the roof putting back up.

The biggest reliability worry for M8 Competition Convertible owners will be its sheer complexity, with so many exotic parts and electronics that could prove eye-wateringly expensive to replace. At least for the first three years most of these will be covered by BMW's warranty.

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As the M8 is a flagship model, BMW has fitted just about every piece of safety kit available, with cameras, ultrasonic and radar sensors all examining the area around the car to help warn of and avoid collisions.