Known in the US as "that expensive Jeep" and globally as the "G Wagon," the Mercedes-Benz G Class has been the statement of choice for celebrities and militaries since the 1970s. With the new G being unveiled late last year, we waited with baited breath for the AMG variant. And here it is.

While Arnold Schwarzenegger might be showing off his one-off battery-electric G Wagon to Jay Leno, most fans of the Mercedes G have been waiting to see what the factory performance arm, AMG, would do with the all-new G Class. Like the G of old, the new-generation of the Wagon brings that square-bodied, rough-and-tumble readiness with its look. Unlike previous generations, however, there is a lot more refinement to justify the triple digit price tag on the Mercedes-Benz G Class: smaller door gaps, better sound dampening, more luxurious interior fitment, and better technology.

Now AMG has had its way and the Mercedes-AMG G 63 looks pretty damn sweet. Side strips with the AMG emblem start off the changes to the new G 63, but more obvious external differences like the wider-spaced slots on the AMG-exclusive grille and large side intakes around a sculpted tubular AMG- bumper guard can also be easily seen. A bit more flair to the wheel arches (to accommodate wider AMG-specific wheels), trim additions to the rear bumper, and "V8 Biturbo" emblems on the fenders are more marks of this AMG-tuned model for the G Wagon.

The external changes tease what's been added underneath. The new-generation Mercedes-Benz G Class added stronger, more lightweight framing and cross-beam stiffening to improve the durability and capability of the G. In the AMG variant, this is augmented by a more robust drivetrain. That starts with a uniquely-designed eight-cylinder engine.

A 4.0-liter V8 now powers the Mercedes-AMG G 63 with twin turbochargers working to help it produce 585 horsepower (430 kW) and 627 pound-feet (850 Nm) of torque. The rpm range for that torque is amazingly low at 2,500 to 3,500. That gives the AMG G 63 a 0-62 mph (0-100 km/h) sprint time of just 4.5 seconds, Mercedes claims. Top speed for the AMG G 63 is a whopping 220 km/h (137 mph) or 240 km/h (149 mph) with the AMG Driver's package.

As interesting as the power output for this new engine is the configuration of its turbochargers. Traditionally, turbos are placed outside of the cylinders, typically above or next to the exhaust manifold. On the Mercedes-AMG G 63, though, the turbos are instead located between the cylinder V of the engine underneath the air handling (intake manifold) normally positioned there. This both makes the engine more compact in footprint, and allows for freedom for the exhaust system which was used to improve emissions by optimizing exhaust flow to the catalyst scrubbers.

Exhaust gases for the turbochargers are ducted to them via separate channels, with each of the twin scrolls in the turbochargers having its own feed. Cylinder exhaust gases are ported to the turbochargers in pairs to reduce exhaust gas backpressure, which improves the gas exchange and results in a reduction of adverse effects from any single cylinder affecting the engine's performance. This also allows optimized flow to keep the turbos spinning for maximum cylinder charging and faster response times (reduction of "turbo lag"). Driver-selectable exhaust notes are possible through a button that engages exhaust flaps at varying degrees.

AMG further modified the 4.0L by optimizing intercooling and making software upgrades alongside some piston modifications for use with piezo fuel injectors. These modifications also allow for AMG's own cylinder deactivation system to allow cylinders two, three, five, and eight to be deactivated (effectively making the engine a four-cylinder) during light-load use such as highway driving. These improvements mean that the AMG G 63 has a fuel economy expectation of about 17.8 mpg (13.2 l/100km).

Along with the engine changes are transmission upgrades. The Mercedes-AMG G 63 uses an AMG Speedshift TCT 9G transmission programmed specifically for the G Wagon. Varied transmission modes change the dynamics, with the standard modes allowing for quick downshifts for speed bursts along with a more comfortable, everyday drive. Sport modes give the transmission more leeway to double-declutch for faster responses and a more seat-pushing feel to acceleration. Direct select of gearing can be made on the steering column.

The new transmission means AMG Performance 4Matic for four-wheel drive. Standard driving in the AMG G 63 is in all-wheel drive with torque distributed in a 40:60 split in a rear bias. The transfer case's low-range reduction ratio is a whopping 2.93, giving nearly triple its torque input to the output shafts. On the road under normal conditions, the transfer case free-wheels in a 1.0 configuration. High- to Low-Range shifting can be made at speeds up to 43 mph (70 km/h).

Also included in the center differential is a sort of mid-tier locking differential mode which uses a multiple clutch to adjust the differential's lock automatically, adjusting to conditions, but this can be overridden by the driver manually selecting the differential lock. This also automatically locks the front and rear differentials through a dog clutch. Selections for individual differential locks are also available to the driver in both low and high range modes.

To all of this, AMG added its own suspension components to improve ride control. Adaptive adjustable damping is standard on the AMG G 63. This is automatically controlled by the G Wagon's computers to optimize ride quality in any given situation. Driver-selectable dampener characteristics can be chosen to range between comfortable and sportier qualities. These, along with steering control and feel, as well as transmission responses are selected through Mercedes' Dynamic Select driving modes system.

Inside the Mercedes-AMG G 63, the AMG touches are also seen. Foremost is the AMG Performance steering wheel, seen in many AMG-branded vehicles. This flat-bottomed wheel is wrapped in nappa leather and fits with the AMG branding seen throughout the G's interior.

At product launch, which will happen at the Geneva Motor Show in March, the Mercedes-AMG G 63 will be offered in an exclusive "Edition 1" model. This will be a limited run of the first few G Wagons in exclusive colors, sport striping, and other details. Mercedes-Benz will begin sales launches on March 18, with global launches through to June.

Source: Mercedes-AMG

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