Top 5 Most Fuel-Efficient Luxury Sedans for 2012

The Mercedes E350 Bluetec is a luxury diesel model that delivers 21 mpg in the city and 32 mpg on the highway. Power comes courtesy of a 3.0-liter turbodiesel engine that makes 210 horsepower and 400 lb-ft. of torque. While not the most powerful model in its class, the vehicle offers good power given the gas mileage. Base Bluetec models start at $51,690 and include 17-inch wheels, automatic headlights, LED running lights, automatic wipers, dual-zone climate control, power front seats with memory functions, cruise control, premium vinyl upholstery, Bluetooth, eight-speaker stereo, six-CD/DVD changer and auxiliary input.

If you can afford the $95,000 initial asking price, then the Porsche Panamera Hybrid is poised to deliver impeccable performance both on the road and at the gas pump. A 3.0-liter V-6 engine mates to a 35kW electric motor to output an impressive 380 horsepower and 428 lb-ft. of torque. Given these gas-guzzling numbers, it is impressive that the Panamera manages an EPA-estimated 22 mpg in the city and 30 mpg on the highway. All Panamera hybrids come standard with air conditioning, power front seats with memory settings, heated front seats, leather upholstery, navigation system, 11-speaker stereo, auxiliary input and cooled glove box.

Base BMW 5-Series models make do with a 2.0-liter turbocharged four-cylinder engine that musters 240 horsepower and 260 lb-ft. of torque. While most competitors start things off with a V-6 offering, opting for the capable four-cylinder results in superior gas mileage (23 mpg in the city and 34 mpg on the highway). At $46,900, the BMW is comparably priced to the Mercedes Benz E350. However, if you're looking to trade in a little of the interior comfort in favor of a sportier drive, then the BMW will likely be the better option. Standard features include 17-inch wheels, automatic adaptive bi-xenon headlights, LED running lights, foglights, automatic wipers, cruise control, dual zone climate control, power front seats with memory functions, premium vinyl upholstery, Bluetooth, 10-speaker stereo, CD player and auxiliary input. All models also come with adjustable drive settings that allow you to fine-tune such things as suspension, steering, throttle and automatic transmission response.

The Audi A6 is another luxury model that benefits from a four-cylinder engine to deliver above-average fuel efficiency. Base models pair a 211-hp 2.0-liter engine with a continuously variable transmission to result in 25 mpg in the city and 33 mpg on the highway. Starting at $41,700, the Audi A6 is also one of the more affordable luxury sedans for the year. Despite this fact, base models are pretty well equipped, with a list of standard features that includes 17-inch wheels, automatic headlights, sunroof, keyless ignition, triple-zone climate control, power front seats, partial leather upholstery, Bluetooth, 10-speaker stereo, CD player, satellite radio and iPod interface. Like the BMW, the Audi A6 also boasts adjustable steering, throttle and transmission settings.

Opt for the Infiniti M35h and you'll get one of the only vehicles that delivers more than 350 horsepower and 30 mpg on the highway. This impressive combination comes courtesy of a 3.5-liter V-6 engine that mates to an electric motor. Exact figures come in at 360 horsepower, 27 mpg in the city and 32 mpg on the highway. Base MSRP for the Infiniti hybrid is listed at $53,700. For that price, you'll get 18-inch wheels, automatic bi-xenon headlights, foglights, power-folding side mirrors, automatic wipers, sunroof, keyless ignition, dual-zone climate control, leather seats, heated front seats, power front seats with memory functions, rearview camera, Bluetooth, six-speaker stereo, CD player and auxiliary input.