The M760Li XDrive is the most powerful BMW ever

The fastest, most powerful and most expensive vehicle BMW has ever produced isn't a slinky two-seat sportster or an electrifying supercar, it's a 2.2-tonne, 5.2-metre luxury limousine that will rocket to 100km/h in a blistering 3.7 seconds.

Oh, and it doubles as the world's most expensive pair of night vision goggles. But more on that in a moment.

Premium bruiser

There was once only one area that truly mattered in the high-flying world of luxury limousines, and that was the sumptuous backseat. That way, the dirty business of actually driving could be left to your minions while you got on with your plans for world domination free from the distractions of ordinary folk.

But BMW's M760Li XDrive is the latest in a wave of go-fast premium bruisers designed not just for plush luxury, but to attack the future with a pin-you-to-your-seat ferocity that's unmatched anywhere else in the executive limousine market.

The M760Li XDrive is a member of the brand's flagship 7 Series range, but its been tickled and tweaked by the madhouse engineers from the brand's fabled M division. And the results are astonishing.

All-wheel power

Hidden under that endless expanse of bonnet is a twin-turbocharged, 6.6-litre V12 (a version of the engine found in the Rolls-Royce Ghost) that will generate 448kW and 800Nm – enough to demolish the 100km/h sprint in just 3.7 seconds. Three point seven seconds. In a car that weighs almost 2.2 tonnes. It's ludicrous. That speed is only possible because the M760Li is the first passenger BMW in Australia to be equipped with all-wheel drive – without it, you'd be spinning your rear tyres into rubber-shredding oblivion every time you stamped on the accelerator.

Those numbers mean it's not just fast for a luxury limo, they make it the fastest and most powerful BMW ever made. In less positive news, it's also the most expensive, arriving in Australia on a per-order basis and wearing a sticker price of $419,000. Yes, that's a lot of money. But if your wallet looks like Kyle Sandilands after a trip to Sizzler, there's few cars that offer the combination of sumptuous luxury and life-affirming power as BMW's ultimate 7 Series.

Sledgehammer style

The power is genuinely immense, and straight line speed unimaginable. Engage launch control, take over the gear changes via the wheel-mounted paddles and stand on the accelerator and the M760Li rockets forward with barely a chirp from the tyres, dispatching 100km/h before powering on to a top speed of 305km/h without so much as a hiccup in its unflinching power delivery.

It can't completely hide its bulk through corners, of course, and it never feels overwhelmingly agile, but neither does it feel like a 2.2 tonne behemoth. BMW knows that its customers are more likely to buy a racetrack rather than lap one, but those that do will not be disappointed.

The M760i feels brutish rather than cat-like, but it's still more than willing to bludgeon corners into submission. It might not float like a butterfly, but it stings like sledgehammer.

But the engine is only part of the story, and BMW hasn't forgotten its customers that want to ride in the backseat. It's a technological masterpiece, and even the highlights list is exhaustive. The sunroof, for example, is stamped with "15,000 illuminative surfaces" that ignite a vibrant blue when the sun sets.

The backseat, too, is a thing of handcrafted beauty, with BMW's outrageously cool Executive Lounge seating arriving as standard fare, allowing you to send the passenger seat forward, where it folds down and in on itself before a foot rest folds out, turning the rear seat into a business class-style flat bed.

Night moves

But perhaps the coolest technology is BMW's Night Vision system that will spot pedestrians or animals when you're driving at night using an infrared camera, and then train a spotlight on anything that might be hiding in the dark.

So, cheap it ain't, but the ultimate 7 Series offers a combination of brute force and plush luxury unmatched by any BMW that's gone before it.

The competition

AMG S65 AMG

The baddest brute to emerge from the Mercedes stable is the S65 AMG, the performance version of the brand's luxurious S-Class flagship. Powered by its own twin-turbo V12, the S65 AMG will deliver 463kW and a staggering 1,000Nm (or, as Mercedes describes it, a "tonne of torque"). It's enough to push the S65 to 100km/h in 4.3secs.

Available as four-door sedan, a convertible or a two-door coupe, S65 pricing starts from a not-insignificant $492,000.

Audi S8 Plus

A comparative bargain, the $330,000 Audi S8 Plus ditches the 12-cylinder engine of its competition, opting instead for twin-turbo V8 that sends 445kW and 700Nm to all four wheels – enough to dispatch 100km/h in a sprightly 3.8 seconds.

Hugely understated from the outside, the meanest Audi is the ultimate V8-powered wolf in sheep's clothing.