Think of what you consider to be a big car, inflate it by about a third and you have the new Mercedes GL63 AMG. At more than 2.1 metres wide and in excess of five metres long, this super-sized, V8-powered, seven-seat SUV is noticeably longer and wider even than an Audi Q7.
The GL63 AMG's 5.5-litre twin-turbocharged V8 engine sends its 550bhp to all four wheels via a seven-speed automatic gearbox. Suspension comes courtesy of AMG-tuned, adaptive air springs and active anti-roll bars.
What's the 2013 Mercedes GL63 AMG like to drive?
We know the twin-turbo V8 engine is seriously mighty, having experienced it in other AMG models, including the E-Class, SL and CLS.
It's no less impressive in the GL. Power arrives in a near-continuous torrent that verges on frightening in something this massive.
In anything less than maximum-attack, the gearbox can feel a little lazy and unwilling to change down when you want it to, although the shifts are smooth and you can always resort to the paddles to make changes manually.
The steering does a fairly good job of making the GL feel smaller than it is. The speed-variable rack is well-weighted and offers a surprisingly delicate response that gives a suitably immediate reaction when turning in to bends.
Its suspension is less successful. Even in its most focussed setting, there's enough body movement to make this a less than confidence-inspiring car to drive quickly.
It feels unsettling as the weight of the car shuffles from corner to corner, and that shifting mass also causes the car's nose to wash wide in fast corners.
The GL63 AMG isn't particularly comfortable, either. Even with the suspension in its softest setting, the ride is jarring over sharp-edged bumps and the car fidgets over scruffy urban surfaces.
What's the 2013 Mercedes GL63 AMG like inside?
Anyone who's driven a latest-generation Mercedes ML will feel right at home behind the wheel of the GL, which gets a similar fascia, including a clear central display for the standard Comand infotainment system and a smaller display between the instrument dials.
Sat-nav, DAB radio, USB socket and Bluetooth are all included, as is climate control, front and rear parking sensors, heated front and second-row seats, a powered tailgate and a sunroof.
The GL 63 raises the stakes with embossed leather sports seats, brushed aluminium trim, AMG-specific dials and multi-function sports steering wheel. The front cabin has a nice blend of quality materials, including double-stitched leather for the top of the fascia.
The middle row of seats provide reasonable space for three six-footers, and even the rearmost seats are big enough to be used by grown-ups although are best-suited to kids if the journey is long.
With the second and third rows of seats folded, the boot capacity can be extended from the standard 680 litres to an impressive 2300 litres.
There's plenty of safety equipment fitted as standard; 20 on-road systems ranging from a 360-degree parking camera to collision avoidance, crosswind assist and a fatigue monitoring system are joined by 10 airbags, including window airbags for all three rows of passengers.
Should I buy one?
For most despite the vigour of its superb engine the GL63 AMG makes no sense at all. If it were a riot to drive then it might at least offer something to justify its 90k price, but the reality is the GL63 AMG is too hampered by its size, weight and unforgiving ride to be particularly fun.
Making a car this big go this quickly is an engineering achievement of sorts, but there are much better cars out there for this money.
What Car? says...
Mercedes GL63 AMG
Engine size 5.5-litre V8 turbo petrol
Price from 91,715
Torque 561lb ft
0-60mph 4.9 seconds
Top speed 155mph (limited)
Fuel economy 23mpg
CO2 g/km 288g/km
By Vicky Parrott