2007 Audi S8

If you think there's no point spending almost $100,000 for something with a 450-horsepower Lamborghini-sourced V-10 engine no one notices, then read no further. Audi's new S8 isn't for you. But if you like the idea of a big, fast, elegantly tailored limousine that slips effortlessly--and rapidly--under the radar, you'll love this car. In an era when AMG Benzes are getting bolder and brassier with every model and BMW's M cars are heading for techno-overkill, the subtle new S8 is the stealth-fighter of sport sedans. In our week with this black-over-gray, German-plated S8 tester, nary a single car-savvy Angeleno's head was turned. And, quite frankly, that's just the way we liked it.

You see, the S8 is a selfish pleasure. Nail the gas and that direct-injection, 5.2-liter V-10 emits a deep, velvety growl--a smooth-jazz remix of the Lamborghini Gallardo's mighty bellow--and gives a satisfying shove between the shoulder blades. You can fan the Tiptronic paddles on the six-speed automatic if you like, but it's better to let the computer do the thinking and allow the tach needle to kiss 7100 rpm on the upshifts, the engine clearing its throat with a soft whump! between each ratio.

Keep your right foot buried, and you'll hit 60 mph in 4.9 seconds and 100 mph in 12.0 and nail the standing quarter mile in 13.4 seconds at 105.6 mph. No, it isn't nosebleed-quick like an S65 Benz (for the record, AMG's ueber-limo nails 60 mph in just 4.2 seconds, 100 in 9.3, and the standing quarter in 12.4 seconds at 116.5 mph, blowing the doors off a Porsche 911 Carrera S in the process). But there's a crispness and flair to the big Audi's power delivery that betrays the Italian soul buried deep in the machine.

That is the engine, of course. The basic architecture is shared with Lamborghini's 513-horsepower, 5.0-liter Gallardo V-10, but the bores have been enlarged to boost capacity. Forged connecting rods allow a 7200-prm redline, and offset crankpins permit an even 72-degree firing cadence, smoothed further by a balance shaft located in the center of the block. The engine uses Audi's FSI direct-injection system, which pumps fuel directly into each combustion chamber at high pressure, allowing a compression ratio of 12.5:1 and more efficient combustion. The result is not only a healthy 450 horsepower at 7000 rpm, but also, thanks to the variable intake manifold, a useful 398 pound-feet of torque at 3500 rpm.

Why a V-10? Audi claims it's the perfect compromise between a V-12, which would need a longer block and suffer from more internal friction from the additional cylinders, valves, etc., and a V-8, which would be more compact, but would have larger, heavier pistons and wouldn't rev as freely as a result. Offset bores mean the engine is just 26.9 inches long, with all ancillaries attached. Just as well, because most of it is hanging out ahead of the front axle.