From the December 2006 issue of Entrepreneur

Want impressive fuel economy, but you're reluctant to give up prestigious, high-end luxury? Three upscale performance business sedans with different energy sources fit the bill: the Mercedes-Benz E320 Bluetec, which runs on the world's cleanest diesel; the Lexus LS 600h L, the world's first full hybrid V-8 powered by a gasoline/electric motor; and the BMW 530i, with a standard gasoline engine and mileage comparable to some hybrids.

The 2007 E320 Bluetec is another addition to Mercedes-Benz's domination of diesel-powered vehicles. Its most fuel-efficient to date, the E320's quiet 3.0-liter V-6 clean-burning turbo diesel engine has the economy of a four-cylinder and the forceful torque of a V-8, producing 208 horsepower. With ultra-low sulphur diesel fuel in its 21.1 gallon tank, Mercedes-Benz claims the four-door sedan delivers approximately 26 mpg city/ 37 mpg highway to travel an estimated 780 miles on one tank of fuel. A caveat: The sedan doesn't meet emissions standards in California, Maine, Massachusetts, New York and Vermont.

The brand-new 2008 Lexus LS 600h L, which goes on sale in the spring, is a long-wheelbase, hybrid, all-wheel-drive luxury sedan. It houses the auto industry's most advanced gas/electric hybrid system and is the maker's first full hybrid vehicle, featuring a 5.0-liter V-8 engine teamed with a high-output electric motor providing power and performance equal to a 12-cylinder engine. The LS 600h L delivers best-in-class fuel efficiency while pumping out more than 430 horsepower. Estimated mileage is expected to surpass Lexus' standard V-8 engine.

A high-end sedan from BMW is the 2007 530i, with improved mileage and new power under the hood in the form of a 3.0-liter, 24-valve six-cylinder gasoline engine with 255 horsepower. The manual transmission model achieves 20 city/30 highway; the automatic version gets 21 city/29 highway. An all-wheel-drive version, the 530ix, is also available.

Jill Amadiois an award-winning automotive journalist and author.