Vehicles like the Audi Q7 TDI have done a lot to change the perception that diesel vehicles are crude, stinky, black smoke-spewers, and the company's lone turbodiesel gets even better for 2011. (Sister company Volkswagen has several other diesels in its line, including the Touareg, with the same engine as the Q7.)

When it comes to performance, the biggest difference is the use of an eight-speed automatic in place of last year's six-speed. This new transmission provides seamless, smooth shifts. The TDI's engine remains unchanged from last year, and is still a pleasure to drive. Upon cold start, diesel noise is barely noticeable, and it gets even quieter as the engine warms up. Thanks to the 406 pound-feet of torque at a low, low 1750 rpm, it takes very little throttle to accelerate or pass in traffic. Braking is precise, and the discs respond seemingly instantly to driver input. Steering is typical Audi: plenty of accuracy without feeling nervous. While the ride is very firm on highways and straight roads and communicates bumps, the big payoff is in the canyons. This is where the large SUV feels more like an athletic sedan, but with tons of torque.

At the track, the TDI went from 0 to 60 mph in 8.6 seconds, which is about a second slower than the gas 4.2-liter V-8 we tested a couple years ago and the 2011 got through the quarter mile in 16.5 seconds at 82.3 mph. Braking from 60 mph took an impressive 124 feet, not bad for a 5400-pound vehicle. Despite having a third row of seats, the 2011 Q7 weighs 27 pounds less than the 2010 Volkswagen Touareg TDI we tested last year. Yet that VW sport/utility vehicle with the six-speed automatic was actually 0.7 second faster to 60 and went through the quarter mile in 16.0 seconds at 83.5 mph. For those who are looking for gas-powered Q7 options, there are two choices: the 3.6-liter V-6 has been replaced by a 272-horsepower, 3.0-liter V-6, and the 4.2-liter V-8 was replaced by a supercharged 333-horsepower 3.0-liter V-6, both backed by an eight-speed automatic.