Mercedes-Benz SL550

Mercedes-Benz SL550

Nearly 60 years after introducing its gull-winged SL, Mercedes-Benz this summer introduces the SL550, just the sixth generation of its standard-bearing sports car. Six generations over 60 years is not a lot, so an all-new model is a big, once-a-decade deal.

The big story with the new SL550 is weight loss. Even though its body is longer and wider and 20 percent more rigid than its predecessor, the roadster's extracted, thermoformed aluminum unibody gives it a curb weight that's 300 pounds lighter. That's a lot of weight to shed. Also ditched: the old 5.5-liter V8 that made 382 hp, in favor of a twin-turbocharged 4.7-liter V8 that makes 429 hp, tied to a smooth 7-speed automatic. Less weight and more power should always equal more fun, and during a June spin on some twisty Pocono backroads, we found the equation to check out once again. The SL550 handles with creak-free cohesion and a feeling of front-to-rear balance – like you're planted at the car's pivot point – that's sublime.

Though the ash and aluminum interior is cool and understated, there's a plethora of tech geekery buzzing within, such as the 600-watt Harmon/Kardon sound system, which has nearly eight-inch subs hidden in the front footwell, freeing up space on the door panels so passengers can be showered with sonics worthy of the fussiest music snob. Other nifty tech features: a "Magic Sky" sunroof that becomes opaque or transparent at the touch of a button, heating ducts hidden behind the headrests that can extend the open-air motoring season deep into Fall, and active seats with side bolsters that firm up as you enter a turn, to prevent your torso from getting tossed around. Those moving seats? Strangely addictive, though one of our passengers joked that she was losing core strength since they do the bracing for you.

A few days into driving the SL550, we struggled to conjure up the buyer of this 100-grand-plus roadster, especially when comparing it to its similarly priced rivals. The SL550's hodgepodge design language of mismatched angles, lines, and cuts lacks the holistic presence – and lustworthiness – of the Aston Martin Vantage. And its steering lacks the directness and immediacy of Porsche's 911.

But perhaps the SL still stands alone. If you want a looker, you'd get the Aston. If you want a purer driving experience, you'd get the Porsche. But it you want a smooth but powerful, fuss-free roadster that's loaded with tech and so well-engineered and built that even at 90 miles per hour, it enables you to speak in a whisper, literally, to a companion in the passenger seat – and be heard – well, then this is your car. [From $105,500; mbusa.com]