The Infiniti QX56 is a leader in the luxury performance SUV class, in both design and performance.This full-size family vehicle has power, strength and style, and is capable of hauling up to eight adults when equipped with a split-bench second row seat. The rugged drivetrain allows the QX to tow up to 8,500 pounds when equipped with a towing package.It’s available in two well-equipped models, with a 400 horsepower, 5.6-liter V-8 engine and super-smooth seven-speed automatic transmission standard on both.Base prices are $61,350 (plus $990 freight) for the rear-wheel-drive model and $64,450 for the four-wheel drive. Several options packages are available from $200 for cargo mat, cargo net and first aid kit (on my 4WD tester) to $4,650 for the Deluxe Touring Package (also on my tester).New for 2013 are standard auto-dimming exterior mirrors, Moving Object Detection added to the Around View monitor system, an upgraded remote control and interface for the Theater Package, and a new Smoky Quartz exterior color.The aluminum-alloy engine with Variable Valve Event and Lift technology and Direct Injection Gasoline system has improved performance and response as well as improved emissions and fuel efficiency, Infiniti says.Response on acceleration was instant, although not neck-breaking, and as smooth as some smaller luxury vehicles. Both models are rated for 14 mpg in the city and 20 on the highway. With some open road and neighborhood driving, I averaged 17.1 mpg, according to the onboard computer.The automatic transmission has Adaptive Shift Control and a manual-shift mode. The four-wheel-drive model has Infiniti’s All-Mode system with Auto, 4H (high) and 4L (low) modes, which distributes torque to all wheels as needed according to road conditions.Four-wheel-drive low mode is intended for serious off-road driving. The system is controlled by a large knob on the center console, which also controls the snow and tow modes. As I had dry roads and didn’t go off-road, I didn’t give the system a workout, but it’s quite capable of going anywhere that its large size will allow it to fix.The QX56 also comes with Hill Start Assist to help prevent rollback as the driver switches from brake to accelerator on steep inclines, a nice feature on off-road mountain trails. The Theater Package ($3,100) came with two seven-inch color monitors mounted in the back of the front headrests.Both monitors include an auto-bright system that adjusts for daytime, clouds/evening and night/tunnel lighting. I didn’t have any young passengers to enjoy the “movie car” feature, but the adults in the second row had plenty of room — actually more head- and legroom than the front. The second row also had two storage compartments in a large center console (trimmed with wood) for the headphones, remote control, games, DVDs or other fun stuff. There were also two cupholders and bottle/map pockets, separate climate controls with overhead vents, floor vents under the front seat, heated seats, a 12-volt outlet, anchors for child seats, and height adjustable three-point seat belts.Second-row bucket seats were as comfortable as the front buckets, and all seating positions, including the third row, had perforated semi-aniline leather with topstitching.Audio quality was impressive, with excellent staging and controls for front and rear speakers. The sound was intimate for even the third row, with speakers in the rear headliner to ensure that sound quality is not compromised by obstructions such as luggage or cargo.Hydraulic Body Motion control reduces body lean in turns, resulting in a luxurious, flat ride for passengers in all three rows. The Advanced Climate Control System with Plasmacluster air purifier, Grape Polyphenol filter and auto recirculation keeps the atmosphere in the vehicle fresh. The high-stiffness frame structure and a special rear body-ring structure around the tailgate are designed to help provide a quieter, more comfortable ride. The QX’s independent double-wishbone suspension and automatic rear-leveling system maintain uniform ground clearance even when towing or hauling heavy cargo, by adjusting the air pressure in the system’s air bladders.Standard audio equipment included a single in-dash CD/DVD player with MP3, SiriusXM radio, USB for iPod or other compatible devices, and streaming audio and hands-free phone via Bluetooth.Infiniti’s standard hard-drive navigation with voice recognition included NavTraffic and NavWeather, and the Zagat Survey restaurant guide. The navigation system, with lots of useful features, was intuitive and easy to program with easy-to-follow audio directions in addition to a split-screen map with the next turn clearly indicated and labeled.The Around View camera system shared the screen, with a “bird’s eye” view helping line up the QX in tight parking spaces and making sure it wasn’t running over a hidden curb or other objects when backing up. A Technology Package ($3,000) included full-speed-range intelligent cruise control, blind-spot warning and intervention, lane-departure warning and prevention, distance-control assist, intelligent brake-assist with forward collision warning, pre-crash front seat belts, and adaptive front lighting with auto-leveling headlights.The 10-way power adjustable driver’s seat and the front passenger eight-way power seat had two-way power lumbar support, and the driver’s seat had two-occupant memory for the seat, steering wheel and outside mirrors.Second-row captain’s chairs had a tip-up function, controlled by a button on the center stack or a lever on the upper seatback, to allow access to the third row.The third-row seatback folded and reclined 60/40 using a button on the side of the cargo area or on the third-row side armrest. While the power third row folded slowly, the second row, when folded and flipped using the remote button, folded quickly — so quickly as to be a safety concern, especially for children standing nearby.Cargo space behind the third row seat was adequate for everyday use, with 16.6 cubic feet of capacity, several tie-downs and a cargo net. With the third row folded flat, there is enough room for DIY supplies or outdoor toys.The QX56 is eye-catching, with a bold front chrome grille, large LED taillights, body-color running boards (located low enough to make entry/exit easy and painless), integrated front and rear splashguards on the wheel arches, and metallic-painted roof rails. The automotive columns of Emma Jayne Williams appear weekly in the Star-Telegram. Contact her at email@example.com .