When it's a complete lineup, the Mercedes SLK will be available with four-, six-, and eight-cylinder engines. We've driven the two more powerful versions, while Mercedes is holding on to a new turbo four-cylinder edition for the 2013 model year.
The "standard" version, for now, is the SLK 350. It's powered by a 302-horsepower 3.5-liter V-6 that pushes its power out to the rear wheels through a seven-speed automatic. A grunter, this V-6 has a typical tenor that either dazzles you or leaves you wanting for a straight six-- or best of all, a flat one. Mercedes posts a 0-60 mph time of 5.4 seconds and limits the SLK 350 to a top speed of 155 mph. That puts it solidly on the same playing field as the Porsche Boxster and BMW Z4, though it doesn't make the same emotional appeal with its exhaust note.
The automatic is programmed with a trio of shift modes, and sports shift paddles and manual control at the shift lever. Sport is where you'll want to be most of the time, since it wakes up the tranny with the smoothest blend of fast gear changes. In Eco mode the shifts are long and syrupy; in Manual mode, we felt some lumps as the transmission tried to shift as quickly as a true dual-clutch transmission. Given the choice, we much prefer shift paddles to lever gearchanges. One requires a hand off the wheel--and one makes far more sense, doesn't it?
The V-6's gusto pushes the SLK's multi-link suspension to its limits with a sharper feel than in the prior version. The SLK 350 can be outfitted either with either a conventional independent suspension or with user-selectable shocks, and all versions have electrohydraulic steering with Direct Steer, which amplifies steering inputs according to the rotation angle of the steering wheel. The hybrid steering system leaves the usual Mercedes play of an inch or so on center for a more relaxed attitude on the highway, and works its way into aggression by the time you're a quarter-past in either direction.
In our experience, the Dynamic Handling package and the adjustable shocks make the SLK more tossable than it's ever been. It's not as wired-in as the Boxster, but what non-mid-engine machine is? Slide up near the tires' limits and the SLK breaks loose softly and gradually, where it's easily brought back on line. Deep potholes still can jar, though. The deeply talented torque-vectoring brakes can clamp onto an inside rotor automatically to tighten cornering lines, and make the 18-inch, 35-series rear tires pretty obedient.
There's much more ballet than bully here--that's the job of the SLK 55. Stuffed to the gills with a 5.5-liter V-8, the 415-hp top dog sends its intentions reverberating through its mean-sounding exhaust. It's capable of 0-60 mph times of under 5.0 seconds, and it sounds like it. Tightened and screwed down even more, the SLK 55 still has a pervasive firmness to the ride, but its shocks have been tuned to demand less from the driver and more from the car--a much better balance for top-down cruising.
Once you get back out on the fun roads, however, you'll find steering is precise, if muted in its feel and feedback, quick to turn and neither too light nor too heavy for quick changes in direction. Body roll is minimal, when in sport mode, and the transmission, Mercedes' seven-speed Speedshift clutched automatic, is a ready partner in either automatic or manual modes. The large paddles are easy to grab even when a shift is necessary while there's still some steering angle dialed in. It's that much closer to brilliance.