Though it may be its most noticeable update, the 2009 Mercedes-Benz SLK's new SLR-style nose (now with 20 percent more Gonzo!) isn't its most important one. Nor is the new rear end, which receives a subtle diffuser and dual, squared-off exhaust tips. No, the big story is under the hood of the mid-range model, the SLK350, where 300 horses are now stabled.
It wasn't long ago that Mercedes-Benz V-8s were making 300 hp. In fact, they still do, provided you consider the Geländewagen something more than a military-history exhibit. But higher-volume models, including the E-, S-, and SL-classes, ditched their 302-hp engines (denoted by "500" badges) for more ferocious V-8s in just the past two years. It hasn't taken long for Mercedes to fill the gap with a higher-powered V-6, and the SLK350 comes bearing the first one to do so.
The increase of 32 hp and 7 lb-ft of torque over last year's SLK350 has come without a terrible amount of effort. A new intake manifold guides air toward six cylinders that benefit from extensive valvetrain modifications. Those changes have raised the compression ratio from 10.7:1 to 11.7:1, but bore, stroke, and displacement, all remain the same. The revisions do allow a rise in maximum engine speed, however, from 6500 to 7200 rpm. To accompany the higher revs, Mercedes engineers have tweaked engine acoustics to make a glorious, resonant tone that fills the cabin. If all that doesn't excite you, maybe you're a green freak. Well, you can rejoice too, because the more powerful engine also sips gas more frugally and emits less C02. If you're just about the performance stats, know that the changes have reduced the SLK's run to 60 mph by 0.2 seconds, to 5.3.
The revised 3.5-liter isn't quite as smooth BMW's 300-hp twin-turbo six, but it makes up for it with quicker throttle response that introduces instantaneous, electric-car-style go at launch. Its comparative lack of torque (the BMW 3.0-liter is rated at 300 lb-ft, the Benz 3.5 at 265) is only noticeable at highway speeds, where the V-6 pushes the speedometer to the right with a bit less urgency than we saw last time we sat in a 135i, even though the 3318-pound SLK wears slightly thinner pants.
But why are we devoting so much space to this engine and so little to the SLK's dynamics? Because not much else has changed with the baby Merc, which remains more of a cruiser than its competition from Munich and Stuttgart. The V-6, however, is a sign of things to come for the majority of the brand's line-up. The C-class would certainly welcome the upgrades, as would the ML350. And with a new E-class right around the corner, expect it to leave the gate with very competitive V-6 in a market where V-8s have quickly fallen out of style. And what better way to show off some fashionable hardware than with the company's cutest model?