If you're seeking a difference between 2007 and the 2008 Audi A8, performance is where you'll find it.
The 2008 Audi A8 remains powered by a 350-horsepower, 4.2-liter V-8 on the standard A8 and extended-length A8 L, while a 450-hp 12-cylinder engine sits in the bay of the top-of-the-range A8 L W12. (The high-performance S8, with its V-10 engine and more aggressive equipment, is covered in a separate review.)
With 330 hp in the A8, Audi’s 40-valve 4.2-liter V-8 offers an extra 20 hp over last year's model according to Automobile.com, as well as an extra 15 pound-feet of low-end torque. Audi claims the A8 will accelerate from 0 to 62 mph in just over 6 seconds; the top speed is limited to 155 mph. The longer-wheelbase, 12-cylinder version isn’t necessarily faster: Motor Trend says the direct-injection V-8 engine "gives up little to the V-12" and squeezes out up to 18 mpg on the highway.
Both versions of the 2008 Audi A8 use a six-speed Tiptronic automatic transmission, which according to Forbes Autos can be "taken through the gears like a manual." “You get an abundant rush of energy when the pedal is pushed,” Cars.com reports, “but considerable downshifting occurs on even moderate upgrades. Fortunately, those downshifts are smooth and prompt.”
The 2008 Audi A8's variable-ratio, variable-assist steering system has been recalibrated to yield more road feel, and the air suspension has been retuned. The adjustable suspension can "induce unsettling wallow when at softer settings" according to ConsumerGuideAuto, though the A8 Audi rides on 19-inch wheels. Cars.com had a different experience, one much more in tune with what TheCarConnection.com’s editors have found: “On narrow two-lane roads, this full-size sedan whips from one curve to the next with ease. It stays beautifully flat while cornering and responds immediately to driver inputs,” they wrote. Motor Trend notes that the Audi A8’s new steering is “great, with perfect feel and weight, but…we didn't know the old steering ratio needed replacing.”