Bigger is better, right? Not if you're a large SUV owner when gas prices top $3.00 per gallon, not when you meet the girl of your dreams and discover she doesn't date guys who subsist on Whoppers and milk shakes, and not when size allows you to be outperformed by your smaller and less powerful brother.

The brothers in question are the 2007 Audi S6 and S8 models. To be fair, company officials claim the S8 reaches 60 mph in 4.9 seconds as compared to the S6's 5.1 seconds, so in that one respect, bigger is better. Thank the S8's generous use of aluminum and an extra 15 ponies, for a total of 450 from the same 5.2-liter V10 used in the 435-horsepower S6. But, with a wheelbase that's two inches longer and a body that stretches an extra six inches, the S8 lacks the S6's balance when pushed on twisty roads. It's simply too long to be driven as fast and aggressively as the more lithe S6, or at least not with the same level of confidence. When attacking tight turns or peaking a crest in the road, the car's length prevents it from feeling nimble. Audi readily admits that weekend canyon carvers will be more inclined to purchase an S6.

That's not to say the S8 can't hold its own. Quite the contrary, as the big Audi offers an adjustable suspension that can be set for comfortable cruising or sporty switchbacks. In either case, the ride is stiff, albeit to different degrees, so you can expect a solid, firm feel when pushing the limits, but don't expect a luxuriously smooth cruise through town. Like the S6, the S8's steering is speed-sensitive, meaning light at slow speeds and heavier as speed increases, and comes up a little shy in the level of road feel and responsiveness one would expect from a top-tier sports sedan. However, beefy ventilated discs ensure consistent, confident braking, leaving no room for complaints in the stopping department.

Also akin to the S6, the 2007 S8's powertrain proves immensely powerful, though lacks the brute force one experiences in, say, the BMW M5. There's a slight delay upon initial tip in of the throttle, after which all 398 lb.-ft. of torque and 450 horses tackle the asphalt with tenacity. With a subsequent roll on the accelerator you'll experience steady, brisk increase in speed. Because of the cabin's isolation from engine noise and refinement that dulls some of the rough edges, the S8's straight-line performance can be hard to appreciate...until you notice the speedometer or increasingly blurry surroundings. Otherwise, clues are scarce, especially since the car tackles the road with equal confidence regardless of whether velocity registers 35 mph or deep into the triple digits.