What Car? Green awards 2008 - Luxury cars
Most luxury cars are motoring heavyweights - big, brash and packing a serious punch.
The Audi A8 is different. By taking a more featherweight approach it wipes the canvas with all other contenders - in the eco-friendly stakes at least.
First off, the all-aluminium body means a significant saving in weight - a crucial element in cutting emissions.
Our chosen A8 also has an efficient 2.8-litre V6 direct-injection petrol engine in its corner. This means it emits CO2 at a rate of just 199g/km, a 11g/km advantage over others in its class.
NOx emissions are also low and, since it's a petrol, you don't have to worry about particulates. Welcome to the most eco-friendly luxury car you can buy.
It's not half bad fulfilling a more conventional luxury car role, either. The cabin is massive, so you'll be able to stretch out in supreme comfort. The boot is cavernous and well shaped, and nobody does interiors quite like Audi. The A8 oozes class with sumptuous materials, slick switches and a peerless standard of fit and finish.
There are also electrically adjustable leather seats, climate control, a CD multichanger, keyless entry and satellite-navigation with voice control.
Its impressive safety roster includes stability control, sophisticated brakes, eight airbags and active anti-whiplash head restraints.
The A8 is a joy to drive, too. The standard air suspension has four settings that let you tailor the car's set-up depending on your needs.
The speed-sensitive power steering makes the car easy to drive in town, but it's a bit short of feel when you're pressing on along a country lane.
Refinement is another of the Audi's strongest points. Road noise is virtually absent, and it's only when you concentrate that you can hear the wind fluttering over the windscreen. Engine noise usually stays in the background, but it can get a little raucous when you're revving hard.
Performance is surprisingly sprightly: the 0-62mph sprint is done and dusted in 8.0 seconds.
The A8 costs you less than most luxury cars, but at £49,995 it still isn't cheap. Residual values aren't as strong as other cars in the class, either, so it's not as sound an investment in the long term.
Still, with that efficient engine returning 34.0mpg, running costs won't be horrific.
The A8 2.8 FSI's only been on sale since August '07, and the fact that most A8 buyers are determined to go the diesel route means there are only a few for sale used.
Franchised dealers are the place to find them. The used-car locator on Audi's website will save you hours of legwork and driving.
Best buy up to £50,000
Audi A8 2.8 V6 FSI SE
Target Price £45,944
Average economy 34.0mpg
Green verdict A motoring heavyweight that treats the countryside with kid gloves
Best buy £50,000-70,000
Mercedes-Benz S320 CDI
Target Price £52,859
Average economy 34.0mpg
Green verdict A sumptuous set of wheels, with a clean-car image to match
Best buy £70,000+
Lexus LS600h LWB
Target Price £78,274
Average economy 30.4mpg
Green verdict Hybrid technology keeps the Lexus clean, yet mean
With thanks to the Eden Project: www.edenproject.com