The standard G550 is powered by a 382-horsepower, 5.5L V8. This engine can push the vehicle to 60 mph in just 6 seconds, according to Mercedes-Benz. The high-performance G63 AMG is powered by a twin-turbo V8 producing 536 horsepower, making the big off-roader almost unnaturally quick. Thanks to a serious mechanical 4-wheel-drive system, complemented by modern electronics, the G-Class has the goods for serious off-roading as well as simply taking on slippery road conditions. The system comes with three differential locks to distribute power in whatever way is best for the conditions. On- or off-road, traction is aided by the electronic stability control system, which also helps distribute power left to right. The G-Class is a truck-like SUV in look and feel, yet its interior is appointed with top-notch luxury materials, including premium leather, burl walnut trim and wood and leather trim elsewhere. Inside, the G-Class provides a very upright driving position that is different from that of any other vehicle from the brand's lineup. The rear seats even have enough room for adults, but they're not as easily reconfigurable for cargo when compared to most modern SUVs. Also, the back door is hinged on the side rather than the top. Cruise control, a dual-zone automatic climate control system, rear heated seats and a parking assistant are included with the G-Class, as well as a heated steering wheel and heated and ventilated multi-contour front seats. There's also a premium, 610-watt Harman/Kardon audio system that also features an SD memory card slot, iPod connectivity and Sirius satellite radio and HD radio tuners. The navigation system includes a 40-GB hard drive as well as live traffic info and Zagat restaurant ratings.