Mercedes-Benz has revealed the first details and images of its monstrous G63 AMG wagon in the run up to the 2012 Beijing Motor Show.

The new G63 AMG will join the diesel-powered G350 in the refreshed line-up, replacing the old G55 AMG model. Along with a new powertrain, the flagship sports variant benefits from a more aggressive exterior design and a more refined and car-like cabin.

An all-new front bumper conveys a sense of more power over the standard bumper fitted to its predecessor, along with a unique grille and larger wheel-arches. AMG’s familiar five-spoke wheels fill out the wheel wells and quad-exhaust pipes are also featured, which exit in pairs below each rear door.

The interior benefits from similar upgrades to the G350, incorporating a new instrument panel with TFT display; large central screen with Comand system, satellite navigation and internet connectivity; Bluetooth connectivity and voice control. Carbon fibre and satin silver surfaces create a premium ambiance on par with the luxury German brand’s passenger vehicles.

Replacing the G55 AMG, the G63 is powered by Merc’s new 5.5-litre bi-turbo V8, with 400 kW and 760 Nm that out-guns the previous supercharged engine’s 373 kW. Above the G63 AMG is the G65 AMG, powered by the familiar 6.0-litre twin-turbo V12 engine, delivering a huge 450 kW and 1000 Nm of torque. Both engines are matched to a four-wheel-drive layout and a seven-speed automatic transmission. Despite the added power, fuel consumption falls more than 13 per cent to 13.8 L/100km.

The 2013 Mercedes-Benz G-Class range will go on sale in Europe later this year.

The future Mercedes G55 AMG has been spied while it performing some winter testing in Sweden. Luckily, this prototype was dressed down enough to reveal a few more details on the exterior changes.

From these images we can see that the new G55 AMG will be fitted with new side mirrors, a revised grille and a new front bumper. The SUV will also get new wheels with a new design and an updated brake system. For the interior, Mercedes will offer a new instrument cluster, a new steering wheel, and a sat-nav screen on top of the dash as seen on the new B-Class.

Under the hood, the Mercedes G55 AMG will have a 5.4-litre twin-turbocharged V8 with around 386 kW and 700 Nm of torque. Mercedes has promised it will work on improving the fuel consumption, but they can only do so much with the boxy design and robust construction. Also rumoured to be in the works is a G65 AMG, powered by a bi-turbo 6.0-litre V12 with 463 kW and 1 000 Nm of torque.