Mercedes-Benz SLK55 AMG (2004-2015): review, specs and buying guide

The absolute epitome of AMG’s early 2000s approach, the SLK55 was arguably one of Affalterbach’s wildest creations, taking the small car big engine formula to the next level. Sold only with a mediocre automatic transmission and weighing more than we’d like, the SLK55 undoubtedly has its flaws. With even full-fat AMG 63 cars now coming with 2-litre four-cylinder engines though, the draw of such a ludicrous car is hard to ignore.

In R171-form (2004 - 2010), output from its M113 5.5-litre naturally-aspirated V8 stands at a strong 355bhp and 376lb ft of torque, considerably more than any of its rivals and enough for a 4.9sec 0-62mph time and 174mph top speed (when equipped with the Performance Package) – for reference, these numbers are near-identical to the F-type V6 S that came almost a decade later. Numbers aside, this engine has superb response with character in abundance.

In this early form, Mercedes applied an ‘F1-inspired’ design with its SLR-esque nose, also fitting those striking multispoke diamond cut wheels similar in design to those fitted to the hardtop SLK55 Black Series of the same generation. 

> Mercedes-Benz C63 AMG (W204, 2008-2014): review, specs and buying guide

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Introduced at the Frankfurt motor show in 2011 was the R172 car, coming with a complete redesign inside and out to bring into the modern age. An increase in refinement, a snappier gearbox, more interior tech and a new 416bhp output make it much more appealing on paper. In reality though, many consider its predecessor to be the model of choice, with a more attractive, retro design, more feelsome steering and a less restrictive exhaust system.

Regardless of which you opt for, the SLK55 has a superb, responsive chassis allowing for brisk progress. If you can look past the frustratingly intrusive ESP system, it’s a thrilling driver’s car of a kind we’ll never see again. 

A V8 AMG might conjure up thoughts of sky-high maintenance costs, but the SLK55 isn’t as ruinous as you might think. The M113 V8 is a reliable unit, with only consumables like brakes, tyres and fuel costing more than a sensible alternative. Road tax isn’t particularly cheap, though, currently standing at £395 and £330 for the R171 and R172 respectively.

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When buying used, look out for corrosion on the rear axle and brake lines, and pay close attention to the roof mechanism – a minor issue with the latches between the roof storage compartment and luggage area can cause it to jam open or closed, with water ingress also reported by some owners. A variety of electrical gremlins can surface following a battery change or jump start, with the optional Airscarf also temperamental for some. Mercedes-Benz recalled the SLK55 for airbag issues, however all of this is covered by the manufacturer and is already likely to have been covered by previous owners.

The classifieds aren’t home to a huge number of examples in 2024, but numbers are evenly split between early and late cars. Somewhere in the region of £13,000 is enough for a leggy R171, but spend closer to £20,000 and sub 40,000-mile Performance Pack cars are within reach – on both generations, this package adds uprated brakes, suspension, an Alcantara steering wheel, 18-inch wheels, carbonfibre interior trim, a limited-slip differential and a raised top speed to 174mph. Opt for a later R172 car and you’ll pay from £20,000, rising to just shy of £30,000 for the very best examples.

Mercedes-Benz SLK55 AMG (R171) specs