The Mercedes SLK is an iconic compact convertible, which offers the benefit of a folding soft top and the prestigious Mercedes badge on the nose.

This small sports car aims to blend the best of a chic convertible, with the refinement and sense of solidity from a metal-roofed coupe, and an engaging driving experience.

As a small convertible, with a folding hard top, the obvious rival for the SLK is the BMW Z4. Other competitors include the stylish Audi TT Roadster and the Porsche Boxster.

What is it?

The SLK is a two-seater sports car which lets occupants enjoy wind-in-the-hair, roof-down driving thrills one moment, and metal roof-up refinement the next.

With the luxury of a folding hard top, rather than a canvas roof, as with the TT Roadster and the Boxster for instance, the Mercedes offers a strong feeling of security on the road for a convertible.

While the Porsche and to a lesser extent, the BMW focus on offer visceral driving thrills, the SLK is more focused on cruising – and unlike rivals, barring the Audi – it is also available with a frugal diesel engine.

What’s it like to drive?

The SLK250 CDI drinks from the diesel pump, and there’s absolutely no chance you’ll forget that when you turn the key; the car assaults the ears with serrated diesel sound and you can feel vibrations through the floor – this engine is noisy compared with many more modern engines.

While this wouldn’t be so much of an issue in a typical car with a sealed roof, it seems like a very incongruous choice of motor for a convertible sports car. Even when the engine has had a chance to warm up it fails to fade into the background, with the bassy thrum of the motor remaining audible to some extent; whether you’re cruising around town or driving the SLK like a sports car, the engine doesn’t seem to suit this machine.

The automatic gearbox is also not the slickest. While it’s perfectly adequate around town, it seems a little dimwitted when driving more enthusiastically. Keen drivers can, however, change gear manually, which works better with faster driving.

As for comfort, the SLK has a firm-edged ride, which does transmit some bumps into the cabin, whether the suspension is in ‘Comfort’ or ‘Sport’ modes. Comfort provides a relatively smooth ride, though car does bounce over bumps when driven briskly. Meanwhile Sport mode makes the ride more bumpy, though the car handles corners slightly better.

The steering is reasonably weighted around corners, giving you confidence in the level of grip left, though it is very light around town. No complaints can be levelled at the amount of power on tap, however.

The engine may be diesel-powered but it offers a huge amount of punch, albeit with a significant amount of engine noise. Whatever gear you’re in the car launches down the road with enthusiasm and even overtaking longer vehicles is a breeze.

One final thing that coloured our impression of the SLK on the road, is the ‘Intelligent Lighting System’. This system claims to switch between dipped headlights and full beam for you, though in our testing it seemed to have a mind of its own, refusing to put beam on when we wanted it and even dipping the headlights at times on twisty bits of road, where the extra illumination would have made driving much easier and safer.

What’s it like inside?

The SLK’s interior feels very solid, but isn’t as tactile or attractive as those in rivals from Audi or Porsche, for instance. The simple layout of controls is easy enough to get used to, while raising and lowering the roof is easy to get to grips with.

The seats are also relatively comfortable, with enough room even for the tallest of drivers. However, the look and feel of the dashboard doesn’t quite live up to the SLK’s high price tag. Additionally, raising or lowering the roof results in a surprising number of clunks and whirrs while in action, while the door hinges on our car were too weak too securely hold the doors open when getting out in tight parking spaces.

Is it practical?

The SLK is no estate car, but it is adequately practical for this class of car. There is space for larger drivers to get comfortable in the two-seater cabin, while the boot is big enough for a couple of weekend bags.

With the benefit of a folding hard top the SLK makes more sense as an all year round car than rivals with fabric roofs.

Should I buy one?

The SLK looks distinctive and has a powerful engine and a solid, spacious interior on its side.

However, the noisy, grumbly diesel engine is likely to put off many convertible buyers. Similarly, the SLK doesn’t shine when cruising or when driving it like a sports car, meaning that’s it hard to imagine exactly who this car is targeting. The price is also very high compared to talented opposition.

Buyers who want a stylish hard top convertible with an economical diesel motor under the bonnet however – and who aren’t fazed by a little engine noise and the ordinary driving experience – may find that SLK250 CDI ticks all of their boxes.

The Facts

Mercedes SLK250 CDI AMG Sport

List price: £37,150
Engine: 2.1-litre four-cylinder turbocharged diesel
Power: 201bhp
Top speed: 151mph
0-62mph: 6.7 seconds
Fuel economy: 45.6mpg (urban), 65.7mpg (extra-urban), 56.5mpg (combined)
Emissions: 132g/km CO2
Euro NCAP rating: Not yet tested