The suspension on the A6 3.0 is on the soft side of sporty, providing the comfort that most buyers want, while still maintaining the driving control one would expect from a German car. Audi's complex front suspension yields absolute control in wet conditions, and that's with front-wheel drive and traction control. It's even better with Quattro. In dry conditions, the front-drive Audi A6 has none of the torque steer common with high-powered front-wheel-drive automobiles.

The new 3.0-liter V6 gives the base A6 energetic performance in just about any driving situation. We drove the A6 in the foothills of the Blue Ridge in northern Virginia, where the engine performed eagerly on uphill grades. Yet it was like a silent partner on the expressway.

The 2.7 T is designed for more spirited performance with a broad band of torque (258 pounds-feet from 1850-3600 rpm) for quick acceleration performance. With the five-speed automatic, it's capable of 0 to 60 mph in just 6.6 seconds, according to Audi.

A6 4.2 covers the 0 to 60 run in 6.7 seconds. More important is the torque from this 300-horsepower V8, 295 pounds-feet from 3000 to 4000 rpm, which gives it excellent passing performance.

The RS 6 delivers lots of torque and the twin-turbo V8 emits a satisfying rumble when cruising that reminded us of a race car. The passing performance is fantastic, as we learned on sweeping Arizona highways. Punch it and you're immediately around slower vehicles.

The standard five-speed Tiptronic automatic that comes on most A6 models is smooth and responsive. We don't miss having a manual. RS 6 features paddle shifters on the steering wheel that are handy for quick downshifts. Leaving the shifter in the auto position allows a quick downshift for making a pass, which automatically upshifts. It will hold it in gear if it detects you are going through curves. We felt little need to use the manual feature.

The six-speed manual gearbox found in the A6 2.7 T shifts smoothly and is enjoyable to use. The manual allows the 2.7 T to accelerate from 0 to 60 mph in just 6.0 seconds, according to Audi.

A6 3.0 comes with Audi's new multitronic continuously variable transmission, or CVT. Bottom line: It works great, with seamless performance and it's very smooth when cruising. It's more responsive than a traditional automatic transmission. (A6 3.0 CVT can accelerate from 0 to 60 in just 7.1 seconds, according to Audi.) Most people don't realize it's not a traditional automatic transmission until told otherwise. And that's really all you need to know about it. Until recently we weren't impressed with CVTs in cars. They seemed a better match for snowmobiles. But Audi's CVT changed that impression. Audi's CVT is more responsive than a conventional automatic. It delivers marginally quicker acceleration performance, according to Audi. Because it lacks a traditional automatic's power-sapping torque converter, the CVT also delivers better fuel economy; EPA estimates 2 mpg better in city driving. The shifter looks like a traditional automatic with Tiptronic. Put it in Drive, and the A6 accelerates much like a car with a conventional transmission. Whether at light or heavy throttle, the engine gains rpm satisfyingly as the car accelerates. It's not the one-to-one relationship that a conventional automatic provides, but the ear and eye agree that the engine and the car are both accelerating. The transmission never actually shifts gears, of course, but it mimics a conventional automatic in feel. Slam the throttle down while cruising and the CVT feels like an automatic transmission downshifting, only quicker. Moving the lever into the "+" and "?" slot allows the driver to shift "gears" just as if it were a Tiptronic-equipped conventional transmission. The shifts are much quicker than a conventional automatic shifted with Tiptronic. The manual feature causes it to act like a manual. When decelerating for a turn, it maintains the ratio so that the engine helps slow the car for the corner, reducing the necessity to use the brakes.

Brakes in the A6 3.0 are progressive and strong. The RS 6 brakes are excellent on the road, very stable under hard braking. (As with racing brakes, it's important to bed the brakes properly on the RS 6.) On a short, quick circuit at Firebird Raceway the brakes were very stable. Like any sedan, however, the mass of the A6 would likely overheat them in repeated hard use.