The seats are supportive and comfortable and adjust 16 ways. A memory feature remembers all the settings for four different drivers (or moods), including climate controls. Front and rear seats are heated as is the leather-covered steering wheel. The center console provides generous storage. The electroluminescent instrument panel adjusts brightness automatically according to ambient light.

A seven-inch color screen displays Audi's Multi-Media Interface, or MMI. The system is designed to minimize distraction while consolidating most of the interior functions giving the driver lots of options without filling the dash with buttons. Unlike the iDrive system BMW developed for its 7 Series sedans, Audi's MMI features a shallow menu structure, meaning you don't have to burrow deeply down through a maze of menus. A key difference between the Audi and BMW systems, in our opinion, is that Audi did not incorporate the climate controls into MMI. The HVAC (heating and air conditioning) system is instead a separate system that uses traditional climate controls mounted high on the center stack. So you don't have to call up a menu to change the fan speed; simply twist a dial. For its part, the MMI screen on the center dash matches the look of the controls. A Return button takes you back to where you were, similar to a Back button on a Web browser.

Attention to detail is one of Audi's greatest assets. Audi officials say customers discover little touches months after buying the cars. A secondary heater in the A8 L designed to heat up the rear quickly. Ambient lighting in the interior allows control of mood in the cabin. Mood lighting is good.

The cabin is insulated well and carrying on a conversation is easy. There's no wind noise in this car and the ventilation system was acoustically tuned to make the climate control as quiet as possible, even when the fan is at full blast.

The audio system uses Bose noise compensation technology just like those fancy headphones you see people using in first class. It works terrifically well, essentially a microphone that samples the sound and sends out sound waves to cancel out undesirable noise. The cabin seems very well insulated for sound. The 12-speaker stereo sounds fantastic, with crisp bass and clear highs. An equalizer matched to the car's equipment and trim specification takes into account changes to interior acoustics caused by the choice of upholstery. A four-way diversity antenna improves AM/FM reception, and a list of all radio stations that can be received in a given region appears at the touch of an MMI button and is constantly updated by the tuner. The six-disc CD changer is in the glove box. Audi has wired the A8 L to accept either XM or Serius Satellite Radio. The OnStar telematics system comes standard, providing operators around the clock who can give directions and provide myriad other types of information. OnStar operators will send help to your location should an airbag deploy and they can locate the car if it's stolen and unlock the doors if you locked the keys inside.

The rear seats are capacious with acres of legroom. Lots of controls are available to the rear passengers including power lumbar support, and there's a fold-down center armrest. Additional heating elements ensure rear passengers get warm air just as quickly as front passengers.

The A8 L comes with 10 air bags, including front knee bags. In a crash, the A8 L's computers quickly determine which dual-threshold, dual-stage air bags to deploy, how quickly to deploy them, and how intensely they should be deployed. It also comes with excellent seat belts. Be sure all your passengers wear them as they are critical to providing protection in a crash.

The A8 L's trunk is big and deep, significantly larger than that of the Mercedes S-Class and comparable to that of the BMW 7 Series. It houses a full-size spare tire.