2013 Mercedes-Benz SLK55 AMG

2013 Mercedes-Benz SLK55 AMG

2013 Mercedes-Benz SLK55 AMG

2013 Mercedes-Benz SLK55 AMG

2013 Mercedes-Benz SLK55 AMG

2013 Mercedes-Benz SLK55 AMG

SLK 55 AMG "It may very well be the most efficient performance car in the world." Huh? I find the statement odd because if this car actually were the "most efficient performance car in the world," Mercedes-Benz would sure as the sun rises trumpet that fact until the cows believed it. But what if the SLK 55 AMG really is the most efficient sports car of them all? Well then, good job, AMG. Just a few short years ago, such a statement would have been laughable at an AMG press briefing. Remember the horsepower wars? The 6200-plus cubic-centimeter engines goosed to within an inch of thermal meltdown? These days, however, we're talking plausible. With a new corporate focus on reducing CO2 emissions 40 percent by 2015, it very well might even be true.

The most powerful ever SLK 55. While there are other bits and pieces that make it an AMG, at the end of all the hubbub (and the 44-page press release!), Mercedes-Benz's in-house tuning arm is really all about just one thing: big engines pumping out big, tire-shredding power numbers. The new SLK 55 is no exception, though it is a little different. Under the long hood sits a special version of AMG's 5.5-liter V-8 (internal code name: M157). Only thing is, the two turbochargers and intercoolers have been removed for "packaging reasons." In their place? Nada. But don't fret, as the new (and newly christened) M152 motor puts out a rather healthy 422 horsepower and 398 lb-ft of torque.

 First and foremost is a slick cylinder deactivation system that is (almost) totally imperceptible. If you really go out of your way to feel and listen for it, you will detect a slight (and I mean slight) shudder when the other four cylinders fire up and the motor turns back into a proper V-8. But in reality, the reactivation just feels like a tiny bump in the road. The M152 also employees high-pressure direct injection (2900 psi), a lofty compression ration of 12.6:1, and start/stop technology. Now, you have to leave the AMG drive selector in C (or Eco) mode to take advantage of both the start/stop and the cylinder deactivation. And most of the time, most people probably will do just that. The end result will net you about 28 mpg combined. Better yet, the car feels mighty quick, especially with the top down.