Mercedes SLK 55 AMG review

The original Mercedes SLK was launched in the mid-nineties, and was the first production car with a folding metal roof. Nowadays many manufacturers have their own take on the theme, but Mercedes has been honing the technology for over 15 years. The new SLK 55 AMG is the fastest and most dynamic SLK to date, yet it's 30 per cent more efficient than the model it replaces. Tough competition in the form of the Porsche Boxster, Audi TT RS and top-spec BMW Z4 mean that the SLK no longer has the compact roadster class to itself.

Our choice: Mercedes SLK55 AMG

The SLK 55 AMG uses a 5.5 litre V8, and even though it's the most efficient V8 engine in the world, it still has 416bhp and 540Nm of torque – making the SLK good for a 0-62mph time of 4.6 seconds and an electronically limited top speed of 155mph. This puts the SLK within touching distance of the four-wheel-drive Audi TT RS, which manages 0-62mph in 4.4 seconds. Open the throttle and the car surges forward at alarming rate – push the roadster past 2,000rpm and a set of flaps open in the exhaust, creating a thunderous rumble as the revs rise. The brakes are also very impressive, applying pressure only to the wheels that need it – improving cornering ability tenfold – but disappointingly the steering still lacks the edge and accuracy of a Porsche Boxster.

Due in part to cylinder deactivation technology, the SLK 55 AMG is 30 per cent cleaner than the previous mode. It manages 33.6mpg and emissions have been cut to just 195g/km of CO2 – which for a 5.5-litre V8 is an impressive feat. However, at £54,950, the SLK is expensive. Considering the Audi TT RS Roadster is around £7,000 less and the BMW Z4 sDrive35is is 10 grand cheaper, you start to wonder how you can justify the extra outlay.

By gaining lightweight alloys and an aggressive bodykit, you won’t mistake the SLK 55 AMG for any other model in the range. Move around to the rear and you’ll notice a small boot spoiler, faux diffuser and four chrome-tipped exhaust pipes. Along with the AMG badging dotted in and out, you’re instantly aware that this is no ordinary SLK. Inside there is a flat-bottomed AMG steering wheel and optional two-tone leather seats, the dashboard is beautifully finished with contrasting stitching throughout and the dials look great. The AMG is certainly the most aggressive SLK yet.

Keep the roof up, and the SLK 55 AMG is actually surprisingly practical, with 335 litres of load space. Fold it down and that falls to 225 litres, but it's still a very usable load area. Roof down motoring is free from buffeting and an Airscarf system blows hot air on to the back of your neck to keep your warm. The SLK's small size makes it easy to drive around town – especially with the roof down.

The SLK is packed with all the safety systems you expect from a Mercedes, including ESP and an array of airbags – it also comes with options including speed limit recognition and head up display. A stiffer chassis and uprated brakes help the SLK 55 AMG on the road, and a folding hard top gives better rigidity than some fabric roofed alternatives. In terms of reliability, the Mercedes comes with a comprehensive three-year warranty and judging by owners’ opinion, the manufacturer performs consistently well in satisfaction surveys.