As luxury sedan go, the Audi A8 is hardly a household name. It's long lived in the shadow of its more popular rivals from BMW and Mercedes-Benz. But that doesn't mean it's been a bad choice. Lightweight aluminum construction, standard all-wheel drive and impeccably trimmed cabin have made the A8 our favorite alternative pick in this segment. But for the third-generation example of this car, Audi seems determined to move the A8 from indie status to full-on blockbuster.

Longer, lower and wider than before, the 2011 Audi A8 -- at least in its "L" long-wheelbase form -- can now lay claim to being the biggest luxury sedan. Of course, the A8 still weighs less than most of its luxury sedan rivals; aluminum construction is once again a key technology here. This year, the A8's 4.2-liter direct-injected V8 is tweaked for more output and cranks out a respectable 372 horsepower. It's matched to a new eight-speed automatic transmission that not only helps boost performance but also notably improves fuel economy as well.

Audi promises sportier driving dynamics for the 2011 A8 thanks to the all-wheel-drive system's decidedly rear-biased power split; the idea here is to provide more of the feel of a rear-drive performance sedan. Under normal driving conditions, power is split 40 percent front/60 percent rear, but up to 80 percent can be sent rearward when needed. For even more athleticism, an optional, torque-vectoring limited-slip differential is available.

This year the A8 is also loaded with enough technological doodads to make even the most jaded of gizmo geeks swoon. A new dynamic steering system can intervene with automatic countersteering in a slide, and can also quicken the steering ratio by 100 percent when parking. There is also adaptive cruise control with stop-and-go capability, automatic emergency braking, and night vision with thermal imaging and pedestrian detection. Audi's MMI electronic interface is still in use but now features an additional touchpad interface that reads fingertip gestures as letters and commands. Google Earth mapping for the navigation system is another A8 exclusive.

Taken as a whole, the 2011 Audi A8 is certainly a keen choice. It has everything we liked about last year's model, but it's now bolder. True, the A8's rivals like the 2011 BMW 7 Series, 2011 Jaguar XJ, 2011 Mercedes-Benz S-Class and 2011 Porsche Panamera offer an advantage as far as engine choices, with hybrid as well as gonzo V8 and V12 versions of their flagship sedans. If the latter is a non-issue, the multitalented A8 stands fully competitive among large luxury sedans.

The 2011 Audi A8 comes in two trims: standard and long-wheelbase L (which provides more room for rear seat passengers).

Both A8 models come standard with 19-inch alloy wheels, adaptive air suspension, Audi Drive Select (allows adjustment of suspension, steering and engine/transmission response), xenon headlights, a sunroof, Audi's Multi Media Interface (MMI) system with a touchpad that can interpret fingertip gestures, a navigation system, cruise control, a power-adjustable steering wheel, leather upholstery, 12-way power front seats, heated front and rear seats, dual-zone automatic climate control, a power rear sunshade, Bluetooth and a Bose surround-sound audio system (with HD and satellite radio, iPod connectivity, a 20GB music server and a CD changer). The L adds park assist (with rearview camera), keyless ignition/entry, power-closing doors, power rear side sunshades and a power-operated trunk.

Option highlights for the A8 include 20-inch wheels, keyless ignition/entry, a night vision camera (an infrared camera to detect animals and pedestrians up to 1,000 feet away), a solar-powered venting sunroof, faux-suede interior trim, various wood accents, a four-zone climate control and a premium Bang & Olufsen audio system.

There are also several packages available. The Premium package includes 22-way power front seats (with ventilation and massaging functions). The Cold Weather package includes heated steering wheel/rear seats and a rear-seat pass-through (with ski sack). The Rear Seat Comfort package adds power lumbar/recline and ventilation, rear vanity mirrors and four-zone climate control. The Driver Assistance package includes adaptive cruise control, a blind-spot monitor, a lane-departure warning system and a pre-braking system. The Sport package (regular A8 only) includes 20-inch wheels, a sport-tuned suspension, a torque-vectoring rear differential, upgraded leather upholstery and the 22-way power front seats.

The A8 L also offers the option of the Executive Rear Seating package, which includes power-adjustable individual rear seats with a center console, footrests, upgraded leather upholstery, a refrigerator and a dual-screen DVD entertainment system. The entertainment system is also offered on the regular A8.

Both the standard and L models come with a 4.2-liter V8 that makes 372 hp and 328 pound-feet of torque. It comes matched to an eight-speed automatic transmission that drives all four wheels.

Despite its substantial size, this is a quick luxury sedan. In Edmunds testing, a standard A8 did the 0-60-mph sprint in 6.2 seconds with traction control engaged and went through the quarter-mile in 13.8 seconds (it's even quicker with traction control disengaged). Fuel economy ratings are impressive for such a large, powerful luxury sedan, as both A8 versions rate 17 mpg city/27 mpg highway and 21 mpg combined.

Standard on all 2011 Audi A8s are antilock brakes, stability and traction control, full-length side curtain airbags, front- and rear-seat side airbags and active front headrests. The optional Driver Assistance package also includes a blind spot monitor, lane-departure warning system (which alerts the driver if the car strays outside of traffic lanes) and Audi Pre-Sense Plus (monitors traffic and alerts the driver if a potential collision is detected.)

In Edmunds brake testing, an A8 equipped with the optional 20-inch wheels and summer tires came to a stop from 60 mph in an incredibly short 106 feet.

Whether taking off from a stoplight or jetting up to cruising speed on the freeway, the 2011 Audi A8 always keeps a solid rush of power on tap. Moreover, the powerful and easily modulated brakes have no problem reining in this luxury liner.

With its rearward-biased all-wheel drive, automatic air suspension and crisp steering response, the A8 handles like a smaller, lighter sport sedan. Yet over broken pavement the Audi flagship delivers a compliant, composed ride fully in keeping with its luxury sedan status.

The interior of the A8 provides first-class comfort, especially in the L version, which boasts a limolike 42.9 inches of rear legroom. In typical Audi fashion, the fit and finish is superb, with generous amounts of wood, faux suede and aluminum accents lending a luxurious ambience.

With the available 22-way power-adjustable front seats (including upper seatback angle) and standard power tilt-and-telescoping steering wheel, finding a comfortable driving position is easy for folks of all body types.

The dash is uncluttered by buttons thanks to Audi's MMI, which handles everything from the navigation and audio systems to the adjustment of the driver-selectable air suspension. The latter is advanced this year via a touchpad interface that has the ability to recognize handwritten gestures.