Auto News 5

For 2010, the Mercedes-Benz S-class gains its first-ever hybrid powertrain, a clear indication that its maker is shifting from a strict diesel approach to efficiency and finally acknowledging the worth of hybrids as an essential step on the path to electric propulsion. What's more, the Mercedes S400 Hybrid is the world's first production hybrid automobile using lithium-ion batteries (the Tesla Roadster is powered solely by Li-ion batteries). Hybrid propulsion systems aren't anything new, of course, but they're still rare in the luxury class, where the Lexus LS600hL has been standing alone for the past two years.

The Q7's 3.0-liter TDI diesel V-6 is a winner. It's so quiet, so smooth, and so powerful. Well, so torquey, I guess I should say, since it has 406 lb-ft, compared with 266 lb-ft for the 3.6-liter gasoline V-6 offered in the base Q7. Cruising at 80 mph on the freeway is effortless, and if you gun it to 90 mph or higher while you're passing, it's as if the engine is not even exerting itself. The powertrain is also very smooth and refined at slower, around-town speeds. It's a very tractable engine, well-mated to its six-speed automatic. Audi estimates a 0-to-60-mph time of 8.5 seconds (not bad for a 5512-pound, 16.7-foot-long crossover) and a range of up to 600 miles in freeway driving, based on the highway EPA rating of 25 mpg and the 26.4-gallon fuel tank.