2012 Mercedes-Benz CLS550

According to the general theory of relativity in the automotive universe, the new Mercedes-Benz CLS 550 must be reckoned as sedate.

By itself, the 2012 version of Benz’s coupe-like four-door sedan looks and feels like a stylish, expensive, high-performance luxury saloon, as the British would say.

But in this circumstance it’s all relative because the CLS 550 has an alter ego. Consider: the 550 arrives with a brand-new, twin-turbocharged, 4.6-liter engine that delivers 402 horsepower to either the rear wheels or all four wheels, depending on the buyer’s preference and willingness to spend an additional $2,200 for the Mercedes all-wheel drive system, called 4Matic.

Relatively speaking, however, all of that pales compared to the 550’s evil twin, the CLS 63 AMG. As any Mercedes fan knows, AMG is the ultra-performance division of the company. It takes already powerful models and, in essence, hops them up—for a whole lot of extra money.

The CLS AMG has a price tag of $23,600 more than the 550. For that, the buyer gets a twin-turbo 5.4-liter V8 with 518 horsepower that goes only to the rear wheels through a seven-speed automatic transmission. It gets the driver to 60 miles an hour in 4.4 seconds with a top speed of 155, compared to 5.1 seconds and a top of 130 for the 550, according to the company’s specifications.

Neither car is cheap. The 550 starts at $72,175 and the AMG’s base is $95,775. Options add many thousands more.

Except for extreme enthusiasts, the 550 should suffice nicely for the well-heeled set that values head-turning design as well as comfort and performance. And in truth, except for subtle styling cues noticeable mainly to the CLS cognoscenti, the 550 doesn’t look much different than the AMG.

The new CLS is the second generation of a car that was introduced in 2006 as a stylish—and more expensive—alternative to the venerable and relatively stodgy E-Class sedan.

The original, which had more subdued, elegant and flowing styling—the guess here is that lot of first-generation owners will prefer their cars to the 2012 version—was one of the more influential, forward-looking designs of the last decade.

The “four-door coupe” design, as Mercedes likes to call it, has been mimicked nearly across the automotive spectrum, from luxury cars like the Jaguar XJ to the mid-size Volkswagen CC and the affordable compact Hyundai Elantra.

As expressed by the 550, the styling features a long, low silhouette with a roofline that extends forward in an arc to the grille and back to the rear bumper. Back in the 1940s, the style was called a torpedo body, but in the Mercedes history book the look was captured in the 1934 Mercedes Autobahn Kourier.

The new 550 has a way more muscular look, with bulging haunches that attract attention all by themselves. They contrast with the flowing lines of the original CLS. Both cars have curb appeal; the difference is in the eye of the beholder.

Although sales totaled just 2,135 in the United States in 2010, compared to 60,922 for the popular E-Class, the Mercedes folks profess to be pleased by its overall sales of 44,500 since its introduction. Of course, they expect the edgier new model to ratchet things up a bit.

One somewhat surprising facet of the new 550 comes in the sought-after—by all manufacturers—improvement in fuel consumption. Though it is doubtful that economy is a deal breaker with comfortable Mercedes buyers, the 550 does get bragging rights with an 18/26 city/highway rating from the EPA. It at least removes the stigma of a gas guzzler tax—no small feat for a car with this turbo power and blastoff performance.

Contributing to the improvement (from 14/21 in the 2011 model) is a Mercedes first—using electricity to power the steering in place of the former hydraulic setup. Though slight in this context, it eases the load on the engine.

The CLS also employs an automatic air suspension system with adaptive damping that delivers sports sedan handling on twisting mountain roads. Especially in the “sport” setting, it moves something like a star soccer player in a tuxedo. Prominent bolsters in the front seatbacks hold the driver steady.

Yet the CLS is a quiet highway cruiser with just enough musical V8 sounds to satisfy enthusiasts. No surprise, luxury touches abound, including the beautiful ash wood trim in the interior of the test car.

The only jarring note is the placement of the power window controls on the insides of the doors. The setup is awkward and not as intuitive as controls on the sides of the seats.

Back seat room is middling, which is to say the seats can comfortably accommodate two humans about 5 feet 10 inches tall or smaller. Mercedes gets a standing ovation here for not pretending that a fifth person could straddle the driveline hump. Instead, the console extends into the rear seat.

The trunk is shallow but carpeted and reasonably useful. Big C-hinges are encased so that they do not crease expensive luggage. The trunk lid must be slammed shut; there is no luxury-car pull-down.

Specifications