Acura, Infiniti, Cadillac, and Lexus have their work cut out for them, because the current contenders for best mid-size luxury car are all very compelling. They also all happen to be German. Audi, BMW, and Mercedes-Benz rule this sector, if not in terms of overall sales, then at least in terms of perception. Executives and engineers from the other makers consider the A6, the 5-series, and the E-class benchmark sedans. But which of these three is the best?
To find out, we took the six-cylinder models on a lightning tour of Bavaria. They're the volume sellers, after all, even if they lack the pace and ultimate refinement of their pricier V-8-engined siblings. The newest car, the Audi A6 3.2 Quattro, is the biggest. It's roughly three inches longer than its rivals and is less than five inches shorter than Audi's flagship A8. But it fails to carve out a significant space advantage, because its exterior dimensions are offset by the shortest wheelbase in this group. As a result, Ingolstadt's midliner provides a little less rear headroom and shoulder room than the other two contenders. The one area where the extra inches pay off is concealed by a deep and wide trunk lid. In suitcase swallowing, the Audi's trunk narrowly outpackages those of the Mercedes and the BMW.
In the premium segment, styling is an increasingly important decider. The E-class scores well here, with a balanced and elegant, if traditional, design. The 5-series tries hard to look stylish, fashionable, and modern. And the A6 combines coupe overtones with a bold grille and a middle-of-the-road rear end. Inside, the visual and functional differentiation is more obvious. The Mercedes is a downscaled but no less opulent variation of the successful S-class theme. The BMW is an ergonomic challenge, utilizing different architectures and materials, which renders it a marginally tighter fit than its challengers. The Audi is airy and contemporary, even more beautifully put together than the Mercedes, and particularly easy to use.
That sentiment certainly applies to Audi's Multi Media Interface system, which is logical and only as complex as you want it to be. The center controller is flanked by four buttons that are directly related to the four major menus displayed by the color monitor. There are also eight access buttons on the center console, which hook you up with the CD player, the navigation system, or the car phone. The drawback is that simple tasks such as changing the radio frequency or cranking up the seat heater require more than one push, click, or scroll. And the buttons on the steering wheel are underwhelming in the variety of functions they are able to perform. The E320 we tested was unfortunately not fitted with the latest-generation Comand system, which is much better laid out but more difficult to access because of its tiny, multidirectional, multitask controller. Although BMW's iDrive is slowly shedding the idiosyncrasies that haunted the original version in the 7-series, the structure of the software is still more function-key than point-and-click, and simple exercises such as selecting split-screen navigation display will have you cursing and moaning.
While most of the extras on these cars' options lists are aimed at improving comfort and convenience, the BMW 5-series actually needs Active Steering (AS) and Active Roll Stabilization (ARS) to evolve from a more generic sedan into something special. Part of the $3300 Sport package, the variable-ratio steering and the self-adjusting antiroll bars give the 530i an advantage in handling and roadholding. While Active Steering is go-kart quick in town or on twisty mountain roads, it feels nicely balanced and relaxed on the highway. With Active Steering, the BMW reaches a new level of feedback and precision, but it takes a while to adjust your driving style to it.
You don't have to pay extra for the unique selling propositions fitted to the Audi. Quattro four-wheel drive, for example, is standard, direct fuel injection comes free of charge, and there's a push-button electromechanical parking brake. Powered by a new 24-valve V-6 that delivers 252 horsepower at 6500 rpm and 243 pound-feet of torque at 3250 rpm, the Audi can accelerate from 0 to 62 mph in 7.1 seconds, which is on par with the 225-horsepower 530i and the 221-horsepower E320; they take 6.9 seconds and 7.1 seconds, respectively, to sprint from 0 to 60 mph. In the United States, the BMW runs out of steam at 150 mph, but the Mercedes is limited to 130 mph. (In Germany, the Audi is governed at a top speed of 155 mph.) The more powerful and heavier Audi is also the thirstiest: while the A6 averaged just under 17 mpg on our test, the E320 returned more than 17 mpg, and the 530i was the most frugal, at just over 18 mpg.
The Mercedes and the Audi are available only with manu-matic transmissions, but the BMW can be ordered with a manual, a sequential manual, or a manu-matic. While you must use the shift levers to effect manual changes on the BMW and Mercedes automatics, the Audi has steering-wheel buttons, which are a real advantage on challenging roads. Although the adaptive autoboxes are pretty good at responding to any variation in driving style, the comfort-oriented E-class in particular prefers early upshifts and late downshifts. It also has the slowest and least progressive throttle, a relatively passive gearbox, and an engine that does not particularly like to rev but, ironically, needs to be revved to deliver.
Despite the dramatic difference in character, the Mercedes is almost as quick as the Audi. On smooth blacktop especially, the E-class stays right on the tails of the other two cars. True, it has woolly controls and a relatively passive drivetrain-but it hangs on like a terrier, despite lots of yaw and roll, howling tires, and stability control that's working overtime. On rough pavement, however, it manages to combine a jittery ride with emphatic body movements and steering that feels light and lifeless. Without Airmatic suspension, this particular specimen sacrifices a core Mercedes quality: best-in-class comfort.
The BMW feels more tied down and more focused. Our 530i was the handling hero yet did a sterling job in compensating for long undulations and low-frequency irritations, as well as providing a reasonable low-speed ride. The AS/ARS package adds dynamic delight to this spine-friendly behavior. Thus equipped, the BMW combines quick steering with the art of total body control, along with more grip than 90 percent of drivers are ever likely to need.
The Audi is less tactile and less sensuous but every bit as competent. For a start, the A6's all-wheel drive can make a big difference in foul weather or on slippery roads. Having said that, Quattro would be more entertaining dynamically if Audi decided to change the torque split from 50/50 to a clear-cut rear bias. The steering is light and linear, but the turning circle is overly large, especially compared with the highly maneuverable Benz. The brakes are, at least subjectively, the best of the lot. They decelerate the car with vigor, they are easy to modulate, and they remain unperturbed even when you're giving them hell.
The new A6 is light-footed and deceptively quick. The Audi does have one big flaw, however. The suspension feels harsh and brittle, and it doesn't really matter whether the car is traveling at 25 or at 65 mph. You can tell that the engineers wanted to create an emphatically dynamic sedan, because they also fitted thinly padded, body-hugging seats, not enough sound-deadening material, and extra-fat antiroll bars.
When it comes down to it, victory does not go to the Mercedes. Even though it was launched just two years ago, in early 2002, the strong-selling E-class is already beginning to show its age. It is well packaged and terrific-looking and has a great overall image, but it is disappointing on the road. Compared with the 530i and the A6, the E320 has the most sluggish driveline, the least engaging steering, and the spongiest brakes. In addition, its chassis is neither particularly comfortable nor very sporty.
Without AS and ARS, the 530i is just a car. Even with these technologies, the 530i's looks and the iDrive system are an acquired taste, and it has the most compromised rear seat. But in terms of responsiveness and agility, a properly spec'd 5-series outshines the competition. The steering, ride, and chassis balance are strong arguments for those who love to drive hard.
If the 530i is the best-handling car, then the Audi must be the most compelling all-arounder. The A6 wins by a nose-despite the choppy ride and the less than compelling steering. Its engine produces more midrange punch, it is fitted with the most intuitive transmission, and it has the best brakes, the nicest cabin, and the most appealing ergonomics. The A6 also eclipses its rivals in terms of traction and stability, and it is comprehensively equipped. It is the pragmatic and rational choice. Although the new A6 may not be the ultimate driving machine, it does offer a greater variety of talents than its esteemed rivals.