All-wheel drive is a feature that only the Audi offers. The good news is that it takes the sting out of driving in foul weather. The not-so-good news is that the Quattro system is starting to age. The S8 is more nose-heavy than its rivals, so it understeers at the limit, which can be frustrating, especially through tight corners. You can step up the pace by switching off stability control, but that opens the door to a random mix of understeer, oversteer, and four-wheel slide. Since the steering, chassis, and brakes are devoid of user-friendly filters and softeners, you feel every bit of what goes on. It takes a while before you can appreciate the Audi's edgy yet honest handling along the thin line between drama and disaster. For the best results, it's imperative to keep up the momentum, choose your line carefully, and refrain from emphatic inputs. Speed is an understated commodity in the S8, but it's there for the taking, and you don't have to be a hero to relish it.
Although the Quattroporte is much better than the '05 and '06 models, its suspension has the same inherent flaws--namely, an unresolved dispute between the springing and the damping and too much lateral compliance, especially in the rear. It's slightly more supple than the Audi, but the Maserati chassis dislikes large obstacles that make its chunky wheels work overtime. The subsequent kicking, pulling, and tugging motions aren't nearly as bad as they once were, but it's the one dynamic drawback that separates this car from true greatness. Thanks to the higher front axle weight, the steering now feels a little meatier, but it has lost none of the turn-in sharpness and crisp feedback. The brakes, although upgraded for 2007, still need to be improved in order to compete with the S63 and the S8. It isn't so much the absolute deceleration that causes one to raise an eyebrow but the initial bite and the slightly spongy pedal feel after heavy use.
The Merc has no such worries. It stops as if neutralizing momentum has nothing to do at all with mass and speed. The energy absorbed by the new fixed-caliper brakes during a day's hard driving would probably light the streets of my hometown from Christmas until Easter. The steering isn't as responsive and intuitive as those of its challengers, but it feels weighty and holds course no matter how bad the surface or the conditions. Another point in favor of the Mercedes is its well-balanced ride. Thanks to its active suspension, the S63 doesn't roll as emphatically as an air-sprung S550, and it refuses to indulge in excessive brake dive and acceleration squat.
In the wet or in anything less than ideal conditions, putting down all that power and torque requires a sensitive right foot and an alert mind. The S63 needs all the microchips it can summon to suppress wheel spin, even in third and fourth gears. Allow the guardian angels to take time off, and the Benz will smoke its rear tires at the earliest convenience. Going sideways through three or four corners in a row can be fun, but it's best to make sure no one is looking, because seventeen feet of sliding S-class is clearly a little antisocial. On dry ground, it's a different story, but even then, there's no mistaking the enormous forces that can peel rubber at a time-warp rate.