When the CTS debuted three years ago, it was the car's odd, angular facets that drew attention. Now that Cadillac's stealth-fighter styling has become familiar, the brand's designers have come up with another kind of buzz borrowed from jets: The sound. Cadillac has tuned the V's 400-horsepower V-8 engine with an exhaust note so throaty that it's easy to imagine you're breaking the sound barrier. I could swear, as I drove down my street, some of my neighbors ducked.

The revival of Cadillac is a standout success story for General Motors. Unlike other GM brands, struggling for distinctiveness and profits, Cadillac has honed an identity as a brash American antidote to bland Japanese luxmobiles and stuffy European coaches. The original CTS made a love-me-or-hate-me statement with its sharply angled body lines. The Escalade outplushed and outgaudied the Lincoln Navigator to become the hip-hop vehicle of choice. The two-seat XLR sports coupe gave Cadillac an icon vehicle at the high reaches of the luxury price range. And now the CTS-V gives Cadillac a sport sedan that can compete with some of the most ferocious racers in conventional clothing, such as BMW's M lineup and Mercedes's AMG vehicles.

The CTS-V is a game challenger. The heart of the car is the 5.7-liter V-8, borrowed from the last-generation Corvette. It's not the absolute latest technology, but it's darn fast—0 to 60 in 4.6 seconds, slightly quicker than the explosive BMW M3. That's a ton of power at your fingertips in regular driving. Give it a little extra tap on the curves, and you'll get real familiar with the flashing yellow light indicating that traction control has been automatically engaged, to prevent a fishtail. Gun it on the highway, and you'll get up to 80 or 90 in the time it takes other cars to reach the speed limit. Just as important, the CTS-V comes with big, sturdy brakes to keep all that power on a leash. A rigid sport suspension and 18-inch tires round out the racy package, which is a thrill on the straightaways and the curves both.

One serious gripe: At certain slower speeds, when you're not accelerating abruptly, the buttery six-speed manual transmission automatically directs the shifter from first gear to fourth, bypassing second and third. This is profoundly annoying. The add-on is meant to improve gas mileage by some minuscule amount, not so much for the owner as for parent company General Motors—which needs every bit of mpg it can get to fulfill its fleetwide mileage requirements. But such interference with the driver's prerogative—something BMW would never do—undermines the car's performance credentials. It's like trick-or-treating on Halloween and getting a toothbrush in your bag. And the six-speed is the only transmission available—which means there's no alternative to the second- and third-gear bypass. There's a work-around, though: Give it a little extra gas every time you start up, which deactivates the deflector. It won't help your mileage, but you might get a few more smiles per gallon.