With the momentum of a runaway Prius, 2008 will see the auto industry's green-minded and fuel economy-conscious fervor turned up a notch as auto makers jockey for credibility and market share with new environmentally friendly powertrains.

General Motors Corp. later this year rolls out its full-hybrid '08 Chevrolet Tahoe/GMC Yukon twins, the industry's first fullsize SUV-based HEVs. Complete with a 25% fuel economy boost, 6.0L V-8 and Two-Mode continuously variable transmission, the Tahoe/Yukon hybrids will join a slew of new GM mild HEVs entering the market, including the all-new '08 Chevrolet Malibu Hybrid and Saturn Aura and Vue Green Line.

Two-Mode co-developer Chrysler LLC will join the parade later in the year with Hemi-powered Dodge Durango and Chrysler Aspen hybrid SUVs, likely as '09 models.

Also wading into the HEV pool in ‘08 will be Audi AG, which confirms a full-hybrid variant of the Q7 cross/utility vehicle, sporting V-6 power, will accompany a new turbodiesel model powered by a 3.0L TDI V-6.

Parent Volkswagen AG will fit the V-6 TDI to the Touareg CUV later in the year, but will first focus on launching the new 2.0L TDI 4-cyl. diesel in the '08 Jetta wagon.

BMW AG and Mercedes-Benz also will be introducing and/or improving their clean-diesel lineups throughout 2008, with all four German auto makers experimenting with AdBlue urea-injection exhaust-after treatment systems for the first time in the U.S.

In stark contrast to improving efficiency, expect wider use of turbocharging, direct-injection gasoline and old-fashioned hot rod ingenuity to push horsepower figures to ever-higher amounts in 2008.

Topping the list will be the supercharged, 600-plus hp Chevrolet Corvette “ZR1,” which is expected to appear early in the year and is aimed at battling the 600-hp '08 Dodge Viper for the title of America's most powerful sports car — ever.