The redesigned 2012 Mercedes-Benz M-Class is available in four different models: a gasoline-powered ML350, a diesel ML350 BlueTEC, a V8-powered ML550 and a high-performance ML63 AMG. All models include 4MATIC all-wheel drive, and share a feature set that's virtually the same --other than their engines. ML350 models come with a new-generation 3.5L, 60-degree V6 engine that's inherently smoother than the former 90-degree design; it also uses high-pressure direct injection, as well as a number of other improvements to produce 302 horsepower while also returning about 2 miles per gallon better (17 mpg city, 22 highway) than last year's gasoline M-Class. The ML350 BlueTEC model comes with a new version of the luxury automaker's turbo-diesel V6 engine--this time making 240 horsepower, as well as an extremely impressive 455 pound-feet of torque and a fuel economy rating of 20/25 mpg. The ML550 returns for 2012, but sports a new, turbocharged 4.6L V8. It makes 402 horsepower, yet manages 20 mpg on the highway, 2 more than last year. Starting at $94,000, the 2012 ML63 AMG delivers track-ready performance without sacrificing all that much comfort. New to the ML63 is a 518-horsepower, 5.5L twin-turbo V8--which makes 550 hp with an available Performance Package. With it, zero to 60 takes just 4.6 seconds and top speed is 174 mph. That top package comes with details such as a carbon-fiber engine cover, painted brake calipers and a special steering wheel. All 2012 M-Class models come with a new 7-speed automatic transmission, and it has done a lot to improve efficiency and enhance performance for all of these powertrains. On diesel models, special electronically mapped hydraulic engine mounts make the BlueTEC driving experience far smoother than virtually any other diesel available. The M-Class models have only two rows of seating and can accommodate up to five adults. They're packaged much like other SUVs, which is to say that rear seatbacks fold forward--along with the lower cushions here--to expand the cargo space up to 71 cubic feet. When the center position of the back seat isn't being used, there's a fold-down center armrest and cupholder, and all four outboard positions in the M-Class are excellent and supportive--contoured for adults and comfortable enough for all-day travel. Upholstery is either a combination of MB Tex synthetic and a microfiber or all-leather. Ride quality of the M-Class models is smooth, quiet and absorbent, yet steering response is quite sharp. That's made possible through a combination of technologies. An AIRMATIC air suspension keeps the body motion under control, while a new Active Damping System makes fine adjustments at the wheels and the Active Curve System works with both systems for better stability. All of those technologies are included with the Dynamic Handling Package. Among the M-Class's many active and passive safety features offered are Lane Keeping Assist, Blind Spot Assist, a Night View Assist night-vision system with pedestrian detection, Distronic Plus smart cruise control, a PRE-SAFE Brake system that will help brake if a collision is anticipated and a special lighting package. Attention Assist studies patterns in the driver's fine steering adjustments, can identify fatigue and drowsiness, chiming and flashing a coffee cup. A revised version of the automaker's COMAND screen-based interface is standard, including a 7-inch display, Bluetooth audio and hands-free calling, cover-art display, a USB port and a 6-disc changer. Meanwhile, the instrument cluster has its own reconfigurable, 4.5-inch display. With the Premium I Package, you add a navigation system with 3D city models and Sirius traffic and weather integration. A special dealer-installed iPad docking station also lets you use your iPad as an entertainment device, integrated with the audio system.