Like the all-new S6, the 2007 Audi S8 draws power from an aluminum, Lamborghini Gallardo-derived 5.2-liter, 40-valve V10 with dual overhead cams and direct injection. Also like the S6, the S8 uses a six-speed Tiptronic automatic transmission to push power to all four wheels through Audi's quattro all-wheel-drive system, a setup that incorporates front and rear locking differentials as well as a center Torsen limited-slip differential. However, unlike the S6, the 4,278-lb. S8 is mostly aluminum, adds an extra two inches of wheelbase, and tacks on nearly six inches of overall length. Thanks to minor changes made primarily to the exhaust manifold, the S8 boasts an extra 15 ponies. That equates to 450 horsepower at 7,000 rpm, while torque remains unchanged with 398 lb.-ft. peaking at 3,500 rpm (90 percent of the maximum torque is available from 2,300 to 6,200 rpm). The V10 was chosen over the 450-horsepower W12 available on the A8 because of weight savings and improved balance. Audi reports a 0-60 mph time of 4.9 seconds, or 0.2 seconds faster than the S6.

Under the 2007 Audi S8's skin is an impressive collection of sport-oriented hardware, such as a performance-tuned, load-leveling multi-link suspension that can be adjusted on-the-fly for firmness and a ride height 20 mm lower than the base A8; a speed-sensitive rack-and-pinion steering assembly that is 10 percent more responsive than when used in the regular A8 application; and the afore-mentioned quattro system, which with its 40 percent front/60 percent rear distribution, offers the slight rear-drive bias preferred by enthusiasts. Those folks will likely also appreciate the attractive 20-inch alloys and 265/35 Z-rated performance tires that fill the wheel wells, behind which is a four-wheel antilock disc braking system using ventilated rotors and bolstered by electronic brake force and electronic brake assistance technology.

Design Subtle cues distinguish the S8 from the A8, including 20-inch alloys, a 20-mm lower ride height, unique badges, alloy mirror housings, and a revised fascia. Inside is a three-spoked steering wheel and limited use of the S8 insignia.

Simply due to their size and presence, not to mention the tastes of their buyers, luxury flagships don't need to be flashy. In regular A8 guise, Audi's largest sedan is best described as understated almost to a fault when compared with the svelte new Mercedes-Benz S-Class or the BMW 7 Series that, despite complaints about its styling, sells quite well. Obviously, pumping things up a bit with a few select visual enhancements couldn't hurt, and that's just what the 2007 S8 does.

Outside, S8 and V10 nomenclature can be seen on the fenders, grille, trunk lid, and brake calipers, while a revised fascia gives the car a more aggressive face. The side profile is differentiated by alloy mirror housings, additional chrome accents on the inner grille, 14-spoke 20-inch alloy wheels, and if the driver has been playing with the suspension settings, an especially keen observer may notice a ride height that sits 20 mm lower than the A8. Similar attention to detail is required to notice four chrome tailpipes rather than the normal two.

It's almost as hard to distinguish the S8's interior from that of the A8. Hints that you're looking at the sport model include a three-spoke, thickly-padded steering wheel and redesigned gauges, both featuring the S8 logo. Gray birch or optional carbon fiber inlays run the length of the doors and width of the dash; real alloy panels reside just below. Collectively, it makes for a beautiful interior, one made all the better when dressed up with the full leather package. But what might really catch your eyes are the tweeters that pop out of the forward corners of the dash. They're part of the 1,100-watt Bang & Olufsen sound system that is also available on the A8.

In addition to being attractive, the S8's interior is designed for optimum usability. The leather-wrapped, power tilt and telescoping steering wheel allows for custom placement, while forward of the properly-positioned shifter reside clearly-marked buttons for the climate control system. Radio controls are largely confined to dials on the steering wheel spokes and the Multi-Media Interface (MMI) center dial, packages oft-used items together for simplified use. Compared to its competitors, Audi's MMI setup is relatively easy to operate, though some of us would still prefer to drop this new level of automotive bureaucracy in favor of simple, clear buttons only.