A thrifty Audi? Yes

Thanks to the BP oil spill, stinking slicks and tarry balls of crude threaten ecosystems and livelihoods as the gunk slouches toward fisheries, bayous, homes and resorts.

All of which made driving the A5 through the magnolia-scented air in southern Mississippi and Louisiana that much sweeter.

The convertible's full name -- A5 2.0 TFSI Quattro Tiptronic -- is a jawbreaker, but the sleek four-seater is Audi's "What, me worry?" riposte to merchants of gloom who say high fuel economy can't coexist with fast, luxurious cars.

The A5 uses Audi's turbocharged, direct-injection 2.0-liter four-cylinder engine to combine effortless high-speed cruising with fuel economy that encourages you to drive past gas stations and consider yourself a friend of the Earth.

The all-wheel-drive Quattro model I tested scored EPA ratings of 20 miles per gallon in the city and 26 on the highway. The front-wheel-drive A4 won't match the Quattro's handling, but it rated 23 mpg in the city and 30 mpg on the highway.

Prices for the 2010 Audi A5 convertible start at $42,000 for a front-wheel-drive model and $44,100 for the all-wheel-drive Quattro model.

For anybody who's wondering about the rest of the car's name, the "T" stands for turbo, and FSI is Audi's name for direct fuel injection.

The powerful and economical 2.0-liter turbo engine is becoming a mainstay of Audi's lineup. It's the only powerplant offered in the 2010 A5 convertible.

The front-drive A5 comes with a continuously variable transmission, while the sportier all-wheel drive gets a crisp six-speed automatic that adapts its responses to match the driver's style.

The very well-equipped car I tested bore a $55,700 sticker price, but Audi figures most buyers will quit checking off options somewhere between $48,000 and $49,000. All prices exclude destination charges.

The A5 competes with other sporty convertibles including the BMW 328ci, Infiniti G37, Lexus IS 250C and Volvo C70. The A5's price compares favorably to those models.

The A5 shares its platform with Audi's brilliant A4 sedan. The convertible's long nose and scalloped sides create sporty looks and proportions, but the convertible's 108.3-inch wheelbase and 182.1-inch length are 2.3 and 3.1 inches shorter than the sedan, respectively.

The combination of the A5's shorter length and convertible top reduce passenger and luggage space compared with the roomy A4 sedan.

The A5's efficient engine and transmission are major pluses, however. They provided excellent performance and economy as I drove the convertible from Detroit to New Orleans this spring.

While the A5's four-cylinder won't out-drag the six-cylinder 328ci or G37, acceleration is good around town and on the highway.

The thrifty engine and transmission consistently outdid EPA projections, returning 27 to 29 mpg in long, fast highway runs.

Well-tuned electric power steering complements the A5's balanced chassis for responsive handling. The suspension absorbs bumps well and keeps the car stable in quick maneuvers.

Despite its lavish options, the A5 I tested suffered from some omissions.

The memory for seats and mirrors did not store the position of the power lumbar supports.

The ventilated front seats don't do much to keep you cool, and the windows do not automatically close with the power roof, making it easy to leave one or more open.

Audi's colorful new navigation system also fell short. Its high-resolution display for the optional navigation system looks terrific, with 3D representations of downtown areas, but the colored lines indicating the route are confusing.