It's the most powerful SLK ever built, yet its 5.5-litre V8 is the world's most fuel efficient V8 engine.
Driving the 2012 Mercedes-Benz SLK55 AMG on a quiet mountain road will immediately dispel any notion you might have that the SLK is strictly limited to the female gender; specifically, cashed-up hairdressers.
On the contrary, the 5.5-litre SLK55 AMG is the most powerful SLK that Mercedes-Benz has ever built, and with a 0-100km/h sprint time of 4.6 seconds, it’s anything but slow.
Visually, it’s a lot more aggressive than the previous Mercedes-Benz SLK, especially the SLK55 AMG, which borrows several design elements from the SLS AMG Roadster. The wider front grille is one such area with its centrally mounted three-pointed star taking pride of place above the high-gloss black finish front splitter.
It features a wider track too, front and rear, so the car looks like it’s well and truly planted. With trademark AMG quad exhaust pipes, rear diffuser and deep front apron, there’s absolutely no mistaking this particular SLK for anything other than the top shelf AMG model.
With all that in mind, Mercedes-Benz Australia should have no problem finding enough buyers for the SLK55 AMG, given the strong and loyal following in this country for the high performance AMG badge that yields a high number of return customers with each new model launch.
The 2012 Mercedes-Benz SLK is actually the third incarnation of the SLK and is also the third generation of the SLK AMG model. Originally there was the SLK32 AMG back in 2001, which was powered by a supercharged 3.2-litre V6 developing 260kW and 450Nm of torque. It was the most powerful vehicle in its class.
Then came the SLK55 AMG in 2004, armed with a 5.5-litre naturally aspirated V8 producing 265kW and a more purposeful 510Nm of torque.
The all-new Mercedes-Benz SLK55 AMG packs the same 5.5-litre displacement, but this new V8 engine develops a more robust 310kW of power and 540Nm.
Hit the oversized starter button and there’s an immediate high-tempo burble that sounds decidedly more racecar inspired than any prestige convertible for the road. It’s more of a metallic exhaust note than its deeper-sounding C63 AMG sibling, but you can hear the SLK55 AMG on approach up to one kilometre away.
There’s a lot of technology in this car, particularly around the engine management system, which deactivates four cylinders during mild throttle inputs for better fuel efficiency, but only when the transmission is engaged in the controlled efficiency mode (C).
However, the moment you require a decent dab of the throttle, the SLK55 AMG reverts to all eight cylinders. The switch from four to eight cylinders would be imperceptible if not for the 'ECO4' and 'ECO8' symbols that appear in the instrument cluster.
Drive the SLK55 AMG with a gentle throttle and it’s capable of achieving an extraordinarily fuel-efficient 8.5 litres per 100 kilometres (combined). Its 5.5-litre V8 is understandably the world’s most economical V8 engine and emits just 197g/km of CO2.
AMG cars have always been fairly hard riding due to stiffer suspension set-ups than the standard Mercedes-Benz cars, but it doesn’t take long to realise the latest SLK55 has a noticeably more comfortable ride than the rest of the AMG fleet. It’s still firm, but even the worst of Victoria’s country roads are ironed out for a largely supple ride.
That’s even more impressive given our test car was equipped with the optional AMG handling package, which adds AMG sports suspension, composite front brake rotors and an AMG rear-axle differential lock.
It’s agile too, with quick response steering on turn-in and nicely weighted for those more enthusiastic driving moments on twisty roads that require multiple directional changes.
High-speed stability is also commendable, and again, that’s on less than perfect road surfaces. It’s a combination of the SLK55’s torque vectoring brake and AMG direct steer system that helps keep the car steady through the bends under heavy loads. There’s a slight tendency for the car to move around on some surfaces during high-speed cornering, but it’s not in any way unsettling.
It’s the same story with the roof down; there’s no discernable scuttle shake in the body regardless of the condition of the road.
Equipped with the 'AMG speedshift plus' seven-speed automatic transmission with paddle shifters, the SLK55 AMG offers smooth shifts up and down the ratio range, even in sport mode (S). It’s a traditional automatic box rather Merc's MCT dual–clutch unit, so the shifts, while smooth, aren’t particularly quick unless you’re shifting up under full load, which shortens shift times.
Drivers can switch to manual mode using the paddle shifters if they wish, but we found the sport setting to be just as rewarding under most conditions.
There’s also an aurally rewarding automatic double-declutching function when downshifting and plenty of that signature AMG burble from the quad exhaust pipes under hard acceleration.
With a kerb weight of 1610kg and AMG four pot calipers at the front, stopping power on board the SLK55 is exceptional, especially under high loads with the car remaining wonderfully composed during such urgent braking.
Despite the short wheelbase the Mercedes-Benz SLK55 AMG is a proper two-seat sports car, so there’s plenty of legroom up front and sufficient headroom with the roof closed for those up to 190 centimetres tall.
Lower the folding metal roof and that AMG exhaust note is amplified tenfold. There’s minimal buffeting too, even at speed and the standard fit Harman Kardon audio system produces superb clarity during open-air motoring.
The standard Nappa leather sports seats are both supportive and hugely comfortable, while the overall cabin is suitably upmarket with sufficient design highlights and high grade materials to make this cabin a very comfortable place to be.
AMG tuned vehicles are rarely referred to as lifestyle vehicles, but the SLK55 AMG is one of those cars that offers buyers a unique combination of exclusivity, outstanding performance and handling, aggressive styling and stance, and a high level of comfort and standard safety kit.
It’s also easy to forget about the unique combination of power and fuel economy offered by SLK55 AMG and that’s something that could motivate a whole new group of customers to the AMG badge.