With Lexus production disrupted last year by the earthquake and tsunami in Japan, the contest for luxury-car sales supremacy in this country came down to a pitched battle between BMWand Mercedes-Benz. The battle was won, by a thin margin, by BMW, although demand for its premium luxury sedan, the 7-Series, fell slightly behind that for the Mercedes-Benz S-Class. Yet each of these heavy hitters would be wise to keep an eye on Audi.

Audi’s premium luxury sedan, the A8, was redesigned last year. While its sales volume still falls well short of the class leaders, its performance does not. For 2012, Audi has expanded the A8 lineup to include a new, ultra-luxurious A8LW12 version with a 500-horsepower, 12-cylinder engine.

Most A8 buyers, however, will select either the basic A8, or the A8L. The ‘L’ signifies a wheelbase stretch of 5.1 inches, which yields a 4.2-inch increase in rear seat legroom. As a test drive of the A8L demonstrated, this results in accommodations that are first class, front and rear.

Up front, a tall driver and passenger should find sufficient headroom and legroom. These front seats are supportive in ways that make them all-day comfortable. The review A8L we drove was equipped with the optional Premium Package, which includes front seats that offer, according to Audi, 22 ways to tweak their position and contours, and several massage modes. These seats are a powerful incentive to lengthen every trip.

In the rear, those extra four inches of legroom give the A8L near-limousine levels of spaciousness. There is one downside, however. The backseat is really meant for two rather than three passengers. Anyone consigned to the center rear seating position will wonder if there is a worldwide shortage of padding material, or did supplies just run a little short on the day this car was made? Consider the A8 to be a four-passenger car, with five-passenger potential for shorter trips.

Performance is superb. The 4.2-liter V-8 is smooth and refined. It is also powerful, having gained 22 horsepower with last year’s redesign. It is now rated at 372 ponies. Working through an extremely smooth and sophisticated eight speed automatic transmission and Audi’s standard Quattro all-wheel drive system, acceleration from any speed is brisk and throttle response is immediate. Sixty miles per hour arrives in just 5.5 seconds with no muss, no fuss and no tire spin on launch, thanks to the allwheel drive. The driving technique required is disarmingly simple: Mash your foot to the floor and experience the thrust passengers in small private jets feel on takeoff. On  secondary roads in eastern Connecticut, the transmission sometimes hesitated before downshifting to pass, but the manual shift paddle provided instant recourse. Give the drive train top marks.