The Mercedes-Benz CL550 we tested is a swift and smooth ride to be sure, but we'd stop short of calling it a sports sedan. It's simply too large, too soft and too luxurious. But it is rewarding to drive for just those reasons.You start the CL with a touch of a big aluminum button to the right of the steering column. We still wonder why being able to keep the key in your pocket makes this a better solution. Then drop it into gear with a column-mounted electronic shift lever similar to the kind BMW is now using. Purists may feel it's an odd and un-sporty throwback to have a shifter moved off of the center console and on to the steering column, but it works well and frees up space.
The 5.5-liter all-aluminum 32-valve V8 is velvety smooth and nearly silent, until you prod it. With 382 hp on tap it rushes the car to speed with a muted, purposeful growl. (For the 2008 model, Mercedes quotes zero-to-60 mph in 5.3 seconds.) The seven-speed automatic gearbox shifts imperceptibly in town, smoothly at full throttle and never gets caught in the wrong gear in traffic. Quiet, smooth, sophisticated: This is the way the powertrain in a high-end luxury automobile should behave.
Having a gasoline-fired engine this powerful pulling a 4486-pound vehicle does create a gas mileage penalty, or two actually. The first is real-world fuel economy: the EPA mileage rating is 15/22 City/Highway. And that figure triggers the federal Gas Guzzler Tax at purchase, $1000 in this case.
If there's one word that describes the CL road experience, it's silken. On smooth surfaces it feels as if it's riding on glass. Some vibration or road harshness must be penetrating the hushed cabin, but it just doesn't feel like it. The sportier BMW 6 Series coupes register bumps harder and reveal surface imperfections far more acutely. In the Benz, the smaller road irregularities get glossed over. Over larger bumps the ride is less supple than you might expect, almost firm, but not enough to inspire the driver to attack the curves.
The steering has a ball-of-silk feel, less sharp than in the BMW and more relaxed in its responses. Though the steering effort rises with road speed, the feeling remains comfortable, smooth and luxuriously isolated rather than sports-car sharp. This is a car that wends its way down a winding road with grace and stability; the active suspension keeps it cornering quite flat. But the CL doesn't communicate the sense of the road in the way that great sports sedans do. It never gives you the urge to get aggressive, as a BMW 3 Series would.
On the highway, the CL's German DNA is fully in evidence. It has a commanding, solid feel and is dead stable even at extra legal speed. It's in these upper speed ranges that you notice that wind noise has hardly increased at all. This is autobahn breeding at work.
Using the optional Distronic Plus distance sensing cruise control is an eerie and fascinating experience. The radar-based distance monitoring system automatically slows the CL, using the brakes if necessary, as you close the gap on the car in front. That distance can be set between a hundred and several hundred feet. When the system detects the lane ahead is clear again, it accelerates back to your pre-set speed. All the driver needs do is steer, an odd sensation to say the least. The system works beautifully in light Interstate traffic and reasonably well in moderately denser intra-urban highway environments, though it sometimes annoyed us by slowing sooner for a car up ahead than an average driver would in most circumstances.
There's more to Distronic than active cruise control. The system is tied into a comprehensive in-car safety network. Distronic will sound an alarm if the driver is gaining too fast on the car ahead, meanwhile priming the Brake Assist Plus system to apply full emergency braking as soon as the driver presses on the brake pedal, no matter how lightly it's applied. If