Just when you thought that large luxury SUVs were destined to be as extinct as the dinosaurs that power these thirsty beasts, Infiniti has plugged the segment into life support with its redesigned 2011 Infiniti QX56. Just as before, the QX remains Infiniti's biggest SUV, but this time around the company has focused on better handling, added refinement and improved fuel economy.

Unlike the previous-generation model, which was related to the U.S.-built Nissan Armada pickup truck, the new QX56 is based on the Japan-built Nissan Patrol, a dedicated all-wheel-drive utility vehicle that is the company's answer to the Toyota Land Cruiser. The shift in platforms for the U.S. means a larger, better passenger cabin as well as a lengthy list of new technology. One interesting feature is the optional Hydraulic Body Motion Control system, which uses interconnected shock absorbers to combat body roll as well as brake dive and acceleration squat.

Under the hood is a 5.6-liter V8. Though it's basically the same engine as before, the adoption of direct injection and variable valve timing and lift brings its output up to 400 horsepower, a healthy rise over last year's 320 hp. Also new is a seven-speed automatic transmission (replacing a five-speed automatic), which helps increase fuel economy by an impressive 14 percent.

Major improvements can be found throughout the cabin, which looks more like a private jet than an SUV. Top-notch materials and craftsmanship define the QX's luxury status, along with plenty of technological features that almost make the driver redundant. The QX still offers three rows of seating and is also noteworthy in terms of cargo capacity, as it's able to accommodate more than its competitors.

There are some areas of contention, however, the most notable being the 2011 Infiniti QX56's bloated exterior styling. Also, the standard 20-inch tires compromise the QX's ride quality and also make this very capable platform unsuitable for off-road use. Light-duty all-terrain off-roading (gravel roads and snow) is about as much as the big Infiniti can handle, as it lacks a locking rear differential and suitable tires. It's also worth mentioning that the third-row seats are suitable for smaller passengers only.

For most consumers the new QX56 stacks up fairly well. The 2011 Cadillac Escalade stands as the Infiniti's main rival, with similar appointments and capabilities. The 2011 Lincoln Navigator is roomier but underpowered. Also worth consideration is the Mercedes GL550 for its prestige and polish. And if you want something with off-roading chops, we'd steer you to the all-conquering 2011 Lexus LX 570 and 2011 Land Rover Range Rover. But with its impressive feature content, secure handling and potent V8, the 2011 Infiniti QX56 represents a solid choice as a luxurious hauler of people and cargo.

The 2011 Infiniti QX56 is a full-size luxury SUV with seating for seven or eight passengers. It is available in either rear- or four-wheel drive, but only in one well-appointed trim level. Standard features include 20-inch alloy wheels, a Class IV trailer hitch, automatic bi-xenon headlights, foglights, heated power-folding exterior mirrors, running boards, roof rails, a sunroof, tinted rear windows, a power liftgate and rain-sensing windshield wipers.

On the inside, the QX56 includes keyless ignition/entry, tri-zone climate control, an auto-dimming rearview mirror, a top-view camera system, front and rear parking sensors, Bluetooth phone connectivity with streaming audio, a heated 10-way-adjustable driver seat with memory (eight-way for the front passenger), leather upholstery, second-row captain's chairs, a power-folding third-row bench seat, wood interior trim, a power tilt-and-telescoping heated steering wheel, a voice-activated navigation system with real-time traffic and weather, and a 13-speaker Bose audio system (with CD/MP3 player, USB jack, satellite radio and auxiliary audio/video input).

Options are arranged in a succession of packages, most of which require the preceding option package. The first option is the Theater package, which adds a twin-screen rear entertainment system and a 120-volt power outlet. From there you can add the Split Bench Seat package which replaces the second-row captain's chairs and center console with a 60/40 split-folding bench, increasing seating capacity from seven to eight.

The Deluxe Touring package tacks on 22-inch wheels, Infiniti's Hydraulic Body Motion Control system, vehicle-speed-sensitive power steering, heated and ventilated front seats, heated second-row outboard seats, upgraded leather upholstery, remote second-row seat-folding control, special wood interior trim, an upgraded climate control system with air purification/filtration, and headlight washers (4WD only). Finally, the Technology package adds adaptive headlights, adaptive cruise control and a host of high-tech safety features designed to either prevent a crash or protect the occupants in the event of one.

Motivating the 2011 Infiniti QX56 is a 5.6-liter V8 that produces 400 hp and 413 pound-feet of torque. A seven-speed automatic is the only transmission offered and features manual shift control with rev-matched downshifts. Rear-wheel drive is standard, with four-wheel drive optional. When properly equipped, the QX is capable of towing up to 8,500 pounds and is aided by a tow/haul mode for the transmission as well as an automatic-leveling rear suspension.

Despite its hefty 6,000-pound curb weight, the QX56 hustles from zero to 60 mph in a quick 6.8 seconds. Due to its high profile and heavyweight standing, handling limits are relatively low. When equipped with the optional Hydraulic Body Motion Control system, however, cornering stability is significantly improved. This system increases hydraulic pressure to the outer dampers in a curve, reducing body roll and providing a much more confident cornering attitude.

It's understandable that the QX56 doesn't impress when it comes to fuel economy. The EPA estimates fuel consumption at 14 mpg city/20 mpg highway and 16 mpg combined whether the vehicle has rear or four-wheel drive. This is the best fuel economy among the Infiniti's competitors by a few mpg.

The 2011 Infiniti QX56 has the same safety features that you'd find on a luxury car, including front airbags, front-seat side airbags, full-length side curtain airbags, traction control, stability control and antilock brakes.

In addition, the QX56 can further protect occupants with the bevy of additional features included in the Technology package. These include a lane-departure warning and prevention system, Distance Control Assist (which alerts the driver to slowing traffic ahead and increases throttle pedal resistance when following too closely), Intelligent Brake Assist (which applies the brakes to reduce damage if the driver does not slow the vehicle), front pre-crash seatbelt tensioners and a blind spot warning system.

Stopping from 60 mph requires only 123 feet, which is a figure we're more accustomed to seeing from a much lighter passenger car. For an SUV of this size, it's downright impressive.

With 400 hp under the hood and seven speeds in the gearbox to keep that power on tap, the 2011 Infiniti QX56 should satisfy most power-hungry drivers. As such, merging onto an interstate and passing slower traffic is effortless. The optional Hydraulic Body Motion Control system works as advertised, keeping body roll to a minimum in the curves and instilling a feeling of confidence.

Unfortunately, opting for the active suspension will also require the addition of the 22-inch wheels as part of the Deluxe Touring package. These wheels and the accompanying low-profile tires diminish the suspension's ability to smooth out potholes and ruts, generally making the QX feel needlessly harsh. Over smooth pavement, however, the ride is pleasantly serene, with no wind or road noise to speak of.

The 2011 Infiniti QX56 envelops passengers in a luxurious cabin where nearly every surface is covered in leather or rich wood trim. Every panel and interior element is tightly fitted, with no detectable squeaks or creaks. With plenty of pockets, bins and cupholders, finding a place to stow your personal effects is never a concern.

The same goes for larger items, as the QX56's cargo capacity is greater than competing luxury SUVs. Luggage space behind the rear seats rates a generous 19.3 cubic feet. Folding the second and third rows flat expands that space to a massive 112 cubes. The QX's boxy shape further enhances its cargo capabilities, allowing it to easily accommodate large bulky items.

As with many Infiniti vehicles, the QX boasts a long list of high-tech features. Besides the ability to play three different DVDs simultaneously (one in the front seats, two in the rear), the second-row screens feature an auxiliary audio/video input. This allows parents to connect a video game console to keep children blissfully occupied. Infiniti even went so far as to ensure that a Nintendo Wii system would fit in the center console.

One feature we found particularly useful is the remote second-row seat folding control, which is part of the optional Deluxe Touring package. This allows the driver or front passenger to remotely fold the second-row seats to allow easier access to the third row, a feature that should prove especially helpful in the rain and for letting children scamper in and out with a minimum of fuss.