Among the many world debuts at this week's Los Angeles auto show is the 2012 Mercedes-Benz ML63 AMG SUV. Mercedes is credited with starting the unique segment with the 2000 ML55 AMG and today the playing field has grown to include competitors from both Germany and Detroit. This is the brand's third iteration of its high-horse powered luxo-ute and the changes should help keep the ML63 at the top of its game.

So what's changed? For starters, the naturally-aspirated 6.2-liter V-8 (codenamed M156) gives way to AMG's new 5.5-liter, direct-injected, twin-turbocharged V-8 dubbed M157, which is already under the hood of several updated AMG models. For those unfamiliar with the M157, smaller displacement thankfully doesn't equate to less power. The turbocharged engine has bigger muscles to flex, with 518 hp and 516 lb-ft of torque -- 15 hp and 44 lb-ft more than the M156. Opting for the AMG Performance Package bumps power up to 550 hp and 560 lb-ft, while increasing top speed from 155 to 174 mph. Better yet, the ML63 will have an estimated fuel economy of 16 mpg combined, making it 33 percent more efficient than the outgoing model.

Added fuel economy gains were achieved by way of adding start/stop technology and a number of improved mechanical bits: a thermal management system for the transmission oil, new axle gears with improved friction loss, and improved "on-demand" control of the electronic steering and accessory drives. Engineers also managed to shave some 99-lbs of weight off the new model. Finally, the AMG-optimized seven-speed automatic carries over, but gets a more fuel-efficient torque converter that features improved bearings. The gearbox features three modes - Controlled Efficiency (required for the ECO start/stop function), Sport, and Manual.

Power is sent to all four-wheels (40:60 front:rear split axle ratio) via Benzo's 4Matic system carried over from the second-gen ML63. However, it's now connected to AMG's new Active Curve System, which features active stabilizers on both axles to improve body roll on turns and curvy roads. Active Curve System also works in conjunction with the AMG sports/Airmatic suspension and Adaptive Damping System. Like the previous model, the air suspension still provides driver selectable Comfort, Sport, and Manual settings.

It's business as usual for the remaining performance bits. Steering is an electromechnical, speed-sensitive unit and big 20-inch high-performance tires are fitted at all four corners (21-inchers are available). Bringing all this mechanical magic to a stop are humongous AMG ventilated and perforated discs (15.4-inches front, 13.6-inches rear).

To set itself apart from its ML350 and ML350 Bluetec siblings, the ML63 AMG sports a number of visual cues that follow the same recipe as most other AMG models. Quad-exhaust tips sit at the bottom of a bold rear bumper, while the flanks are highlighted by the aforementioned AMG rims along with "V8 Biturbo" badges. The most dramatic changes take place up front, where designers have created a bulbous hood with two air intake and an aggressive front fascia with standard LED daytime running lamps and a matte silver chrome strip fitted at the bottom of the skirt.

Inside, virtually everything is wrapped in the leather with double-contrast stitching, while the AMG sport seats featuring the brand's designo trim provide added lateral support with oversized bolsters. Passengers will also find a long list of standard features such as heated/ventilated front seats, navigation, Bluetooth handsfree phone and audio streaming, and AMG illuminated door sills. Also standard is the usual alphabet soup of safety tech found in the previous model plus a few new items pulled from the S-Class flagship. Among the safety nannies is Attention Assist, which uses a number of sensors to detect and alert drowsy drivers.

With the BMW X5 M, Jeep Grand Cherokee SRT8, and the Porsche Cayenne Turbo already terrorizing the streets, the 2012 ML63 AMG can't come soon enough. Mercedes-Benz says it should roll into showrooms no later than spring of 2012. Shortly after you can expect the ML63 - along with the aforementioned SUVs - to roll into our garage to decide which four-wheeled SUV is top dog.