2006 Cadillac STS-v vs. 2006 Mercedes CLS55 AMG

In the beginning, there was Eldo versus Mark III and IV, a recurring battle of personal luxobarges referred to as "King of the Hill" by Motor Trend in the 1970s. As the years went by, Lincoln departed Ford's Premier Automotive Group, and General Motors announced its intention to remake Cadillac the "standard of the world." Other European brands have more sporting intentions, but none owns the fast German autobahns more than Mercedes's torque-rich AMG machines, the CLS55 being one of its newest--and sexiest. Its AMG-built 5.4-liter V-8 mit kompressor is good for 469 horsepower and a pavement-pounding 516 pound-feet of torque that pushes 4307 pounds of steel, aluminum, plastic, leather, and suede.

But Cadillac is fighting back with its own 469 horses, complements of its new GM Performance Division-engineered Northstar V-8 SC, in one of its most powerful American production cars ever. The blown 4.4-liter makes 439 pound-feet at 3800 rpm in an upright, full four-door sedan. Before you reach for a pen or Blackberry, know we tried to get an E55 AMG to rub against the Caddy, as it more resembles the STS-v in terms of roofline and price. But Mercedes couldn't come up with one during our test window and offered this instead. The mechanicals are the same; simply adjust the base MSRP downward by about five grand for the E55.

Seventy mph is legal on most Michigan Interstates, and it's a quick shot through Northern Indiana and Chicago to Milwaukee, although the last two will seriously slow you down. Milwaukee has a large German-American population, a history of brewing beer, and a cool, avant-garde architecture art museum for photography. So we took I-94.

The flog began at a German-sounding American course, the "Lutzring" (a track at GM's Proving Grounds) for a test of each car's handling abilities. At this venue, neither exhibits super quick or communicative steering, but both handle more like sport sedans than full-size luxury cars. On public roads, the CLS55's heavy steering and wide AMG tires become a deficit at low speeds. At parking-lot pace, it feels like non-assisted steering. On the track, the Mercedes's five-speed automatic gets confused, not always knowing whether to downshift or upshift when you toe in and back out of the throttle.

The Caddy features the first application of GM's smooth new six-speed automatic, which serves the STS-v well at the Lutzring, whether you tap the gearshift up and down or let its sport mode pick the right gear, usually second or third here. The STS-v is biased toward understeer, while the Cad's attitude is neutral around the 'ring. It doesn't rotate until it's too late and then oversteer whips the tail. The Benz lets you steer with the throttle, progressively wagging its tail out.