Once underway, the G 63 AMG 6x6 proves remarkably easy to drive. It may have been conceived for the rough-and-tumble of army duties in the Australian outback, but the work put in to converting it for civilian use has produced a straightforward nature together with level of comfort you'd hardly credit from such an extreme-looking machine.
In the dunes of the Dubai desert, the G 63 AMG 6x6 feels invincible. Those big tyres work with the complex driveline to provide plenty of traction, allowing you to wind it up to regular motorway speeds on narrow sandy tracks without any great trepidation.
It cruises with great authority, providing longitudinal stability – far better than the regular G 63 AMG owing to the longer wheelbase and added traction provided by the third axle. There's far less vertical movement through the suspension than the standard car, resulting in a surprisingly smooth ride. There's plenty of lean in corners, but body movements are controlled thanks to a unique spring and damper package developed specifically for the G 63 AMG 6x6.
Despite its weight, it accelerates with great vigour. Heady torque combines with the traction-enhancing qualities brought by the six-wheel-drive system to deliver impressive off-the-line and in-gear qualities. Mercedes won't quote official acceleration claims just yet, but insiders suggest 0-62mph in less than six seconds. Top speed, limited by its balloon-like tyres, will likely be electronically governed to 100mph.
And consumption? Again, Mercedes is yet to publish official figures, but we're told to expect around 15mpg on the European test cycle. It's just as well that the G 63 AMG 6x6 will come with two fuel tanks with an overall capacity of 159 litres.
The prototype's vague, hydraulically-operated steering, which is geared at a lazy 3.4 turns lock-to-lock, indicates the need for some fine-tuning to better suit the big tyres. But any doubts about dynamic ability on the back of its rugged good looks were quickly dispelled.
Even when confronted with steep dunes and daunting sink holes, the hulking SUV managed to take it all in its stride, powering on with determination and a baritone exhaust note. Excellent wheel articulation and myriad diff lock combinations keep all six wheels firmly planted on the ground for impressive progress. An onboard compressor with four 20-litre tanks fitted along the sides of the underbody allow you to adjust tyre pressures, taking just 20sec to increase from a stand-friendly 0.5bar up to the 1.8bar required for on-road use – much faster than a conventional system that typically takes around 10mins.
The only thing I've driven that comes remotely close to the feeling I got while at the wheel of the G 63 AMG 6x6 is the Hummer H1. But while the former is incredibly nimble for something so vast and hugely powerful, the latter was stodgy and rather lethargic.
You could argue long and hard about the merits or otherwise of the G 63 AMG 6x6 – surely the world's first road legal MUV (monster utility vehicle). However, one thing holds true: it is a fun thing to drive in the right conditions.
But with a price tag more than three times that of the G 63 AMG, it is going to be a super-exclusive proposition for all but the mega-rich.
Mercedes-AMG G 63 6x6
Price £370,000; Engine V8, 5500cc, twin-turbo, petrol; Power 536bhp; Torque 576lb ft; 0-62mph 6.0sec (est); Top speed NA; Gearbox 7-spd automatic; Kerb weight 3775kg; Economy 15mpg (est); CO2/tax band NA