Mercedes-Benz SLK55 AMG

To some drivers, a special engine can make a car special. An NSX owner will happily tell you his engine has titanium connecting rods. The Corvette ZR1 has a special viewing window built into the hood to help generate conversation. Those driving an SLK55 AMG of the latest vintage might not know it, but the 415-hp V-8 tucked under the roadster’s hood might well be the most special engine in Mercedes-Benz’s lineup. Mercedes puts the AMG stamp on nearly every vehicle in its portfolio. Currently, the “63” AMG cars get a naturally aspirated 6.2-liter V-8 (five models) or a twin-turbo 5.5-liter V-8 (six models). The three “65” AMGs, however few are sold, get a behemoth 6.0-liter V-12 that’s force-fed an air diet by, again, two turbochargers. But the SLK55 AMG stands as the only AMG model with its own engine, a naturally aspirated 5.5-liter V-8 internally known as M152. 12,700 premium over the V-6 SLK350—the base price also tops those of the Porsche Boxster S and the BMW Z4 sDrive35is.

4750 AMG Handling package, which raises the speed limiter to 174 mph (we actually hit 175 in our testing) and includes a limited-slip differential, the AMG Performance suspension, and brake discs upgraded with lightweight aluminum hats. The standard AMG treatment brings front and rear fascias that imply just the right amount of athleticism without drawing too much attention. And a quick-turning (2.2 turns lock-to-lock), small-diameter steering wheel sets off the interior. As with all AMG V-8s, the SLK’s revs freely and makes haste for its redline (7200 rpm in this case). The accompanying soundtrack, especially with the top down, borders on addictive. Mercedes’ seven-speed automatic shuttles along the power and 398 lb-ft of torque using an AMG-spec clutch pack in place of a torque converter, although in this application, launch control isn’t part of the deal. The SLK’s big brake calipers, clamping on 14.2-inch front rotors and 13.0-inchers out back, work with Continental ContiSportContact 5P tires to stop the car from 70 mph to 0 in 159 feet. Skidpad performance is strong, too, at 0.93 g—a healthy advantage over the 0.88 g of the Z4 35is. AMG-spec 18-inch wheels show off the big brakes.

The seats are plenty comfortable and offer ample support in aggressive driving. The steering is free of dead spots, and turn-in is crisp, although feedback is lacking. The car as a whole seems set up more for touring. It can hang, but hustling the 55 through a sequence of turns requires more work than in, say, a Boxster. Back off a bit, and the car flows elegantly into and out of bends, like a great GT car. Note to anyone planning a trip in this SLK: The 10-cubic-foot trunk shrinks to six cubes with the top retracted. And when the top is up at freeway speeds, it makes a bit of noise as it flexes. Despite the direct-injection V-8’s engine stop-start function and cylinder deactivation that kills half of the fire holes, we averaged 18 mpg, 1 mpg below the car’s EPA city rating. Long-distance cruising improved things only slightly: Our best average was 24 mpg—four fewer mpg than the EPA highway number—seen over one tank on a freeway jaunt to northern Michigan. Blame that great engine sound. You know what’s more special than the engine?

A similar situation applies to the driven rear axle. Here too, the sophisticated basic design involving independent wheel suspension on semi-trailing arms has been retained, but the development engineers have completely reconfigured the springs, auxiliary springs and shock absorbers and designed new bearings for the shock absorbers. The new bearings for the control arms have been designed with a special emphasis on comfort, with separated functions for longitudinal and lateral forces. The anti-roll bar and its bearings are also new developments. These developments provide for extremely precise, predictable and safe handling accompanied by outstanding comfort, running characteristics and noise levels. The Vanio offers the very highest standards of ride comfort, driving enjoyment and driving safety. Such all-round quality can only be topped by the air suspension including automatic level control on the rear axle, which remains available ex-factory. Noise has also come in for close attention. Extensive computer simulations and ongoing monitoring of the results on the actual vehicle have enabled a marked reduction in noise levels. The balancer shafts in the new four-cylinder diesel variant ensure that so-called "second-order" vibrations are eliminated at source.

There are no luggage constrictions to be considered when packing for journeys in the versatile and flexible Mercedes-Benz Viano. The development engineers have raised the permissible gross vehicle weight, accompanied by increases in the payload which are quite substantial in some instances. The permissible gross vehicle weight now totals 2.80 t (previously 2.77 t) as standard, while for the extra-long variants it stands at 3.05 t (previously 2.94 t) following the introduction of the new generation. According to model variant, the increase in payload may amount to as much as 100 kg. Comfort and safety in an attractive guise: the Ambiente variant of the Mercedes-Benz Viano now runs as standard on five-spoke 17-inch light-alloy wheels fitted with 225/55 R 17 tyres (previously 16-inch wheels with 225/60 R 16 tyres). This wheel and tyre combination is available for the other models as an option. The Mercedes-Benz Viano comes with an unparalleled range of safety and assistance systems as standard. All models feature a brake system with powerful and robust disc brakes on all wheels, electronic brake force distribution (EBD) and adaptive brake lights which display an emergency braking signal when the brakes are fully applied. Numerous invisible safety features are also on board. The ESP Electronic Stability Programme with anti-lock braking system (ABS), acceleration skid control (ASR) and brake assist (BAS) is obligatory for all Mercedes-Benz Viano models.