The family of Mercedes ML models, together referred to as the M Class, cover a range of duties from family-hauling and cargo-hauling errands to moderate off-roading-all in comfort and luxury. The base ML350 has a 268-horsepower, 3.5L V6 engine, while the mid-range ML320 BlueTEC has a 3.0L turbo diesel V6 that offers the power of a V8 with the fuel economy of a 4-cylinder, according to Mercedes. Thanks to a special urea additive Mercedes calls "AdBlue", it burns much cleaner than last year's CDI, allowing it to be emissions certified in all 50 states. The ML550 features a 382-horsepower, 5.5L V8 engine, and at the top of the line is the ML63 AMG, with a powerful 503-horsepower, 6.3L AMG-built V8. Each model comes with a 7-speed automatic transmission. Both the V6 and V8 utilize variable valve timing and a 2-stage intake manifold for good throttle response whether in stop-and-go traffic or passing at high speed. The ML550 can accelerate to 60 mph in 5.6 seconds, according to the manufacturer. The ML350 is available in both 2-wheel drive and 4-wheel drive 4Matic configuration. All other ML models include the 4Matic full-time 4-wheel-drive system standard. 4Matic has a low range for off-roading and a sophisticated traction control system assists the drive system and incorporates a downhill speed regulator and hill-holder for stability on steep slopes with limited traction. The ML is built on a unibody platform and has an independent suspension-double-wishbone front suspension and 4-link rear setup for good, carlike handling and a smooth ride. Standard safety features on the ML include front side air bags, side curtain air bags that span all outboard occupants, active headrests to help prevent whiplash, and the PreSafe system, which prepares safety systems for an anticipated crash. The M Class has spacious seating for five adults, and the 60/40-split second row folds forward to expand the cargo area when needed. The stylish interior especially stands out for its available burl walnut or aluminum trim. Standard equipment includes dual-zone climate control, power front seats, cruise control, a power sunroof, a multi-function steering wheel, dual heated side mirrors and a retractable cargo cover. The ML320 BlueTEC has similar equipment to the ML350, but the ML550 adds heated front seats, larger front brake discs, burl walnut trim, running boards and a rain sensor. At the top of the line, the ML63 AMG brings Airmatic suspension, huge 20-inch alloy wheels, a new Racetimer for on-track use, an AMG Nappa leather interior with sport seats, burl walnut trim and a CD changer. Major options through the line include the COMAND in-dash multi-media interface and navigation system, the height-adjustable Airmatic air suspension with active damping, a harmon/kardon Logic 7 sound system with auxiliary input, a rear-seat entertainment system, heated rear seats, an ambient lighting package, and bi-xenon headlamps that swivel to help illuminate into corners. The M-class gets a number of exterior design updates for the 2009 model year, including a variety of revised wheels, new larger 3-louver grille (with large rectangular air inlet on ML63 AMG models), new side mirrors, new roof rails, and redesigned headlights and taillights utilizing the latest in projector beam and LED technology. A new BlueTEC diesel powertrain replaces last year's M320 CDI and is clean enough to be legal for sale in all 50 states. A new 2-wheel-drive ML350 is also now available. The latest generation of the Mercedes-Benz COMAND system is also now featured, which includes Bluetooth capabilities, and an available audio unit uses voice controls, has a wireless cell phone link and has other optional features including navigation with real-time traffic updates. The PreSafe accident avoidance system is now standard. Comfortable ride and seating; off-road ability; fuel-efficiency (ML320 BlueTEC); acceleration (ML550 and ML63). Mercedes-Benz's 2009 M Class is on-road friendly and a good family hauler, with improved ride and handling, while still maintaining its off-road ability. The ML320 BlueTEC is clean enough to be sold in all 50 states while still being notably fuel-frugal as well as luxurious. The ML550 adds more luxury and power, and the ML63 AMG leads the pack in exclusivity.