Mercedes SLK cabriolet
Price £33,150 - £55,345
- Stylish design
- High quality cabin
- Folding metal roof
- Quite expensive
- Poor rear visibility
- Not as fun to drive as some rivals
At a glance
"The Mercedes SLK is a stylish sports car with a folding metal roof, which offers luxury and reasonable running costs thanks to a range of efficient engines."
The Mercedes SLK is a rival to the Audi TT Roadster, BMW Z4 and Porsche Boxster, and while the Porsche is the most exciting sports car of the group, the Mercedes feels the most luxurious. Its lovely interior makes long-distance drives a pleasure, and in combination with a relatively large boot, makes the SLK an appealing everyday proposition.
There's a choice of two turbocharged petrol and one diesel engine, while a V6 petrol offers Boxster-baiting performance and a thirsty V8 sits at the top of the range. Surprisingly for a sports car, we’d say the diesel is actually the pick of the bunch, because its mid-range acceleration is well suited to the character of the SLK and offers temptingly low running costs.
Both the Audi TT Roadster and BMW Z4 are cheaper than pricey SLK and adding options doesn't do it any favours. That said, the SLK is desirable and should hold its value well.
It feels like a grown-up choice too, with its secure and winter-friendly hard-top roof, while the cleverly designed windscreen and wind deflectors help keep the cabin from being too blustery with the roof down.
MPG, running costs & CO2
The diesel-engined Mercedes SLK 250 CDI returns very impressive fuel economy
Unlike some of its rivals, the Mercedes SLK is available with a brilliant diesel engine capable of 56.5mpg and just 132g/km of CO2, costing £130 each year in road tax. These are impressive figures for a sports car, beating the diesel Audi TT Roadster TDI’s 51.4mpg and 144g/km. But the Audi does boast four-wheel drive rather than the Mercedes SLK’s rear-wheel drive.
The entry-level SLK 200 petrol returns 41.5mpg and emits 158g/km costing £180 in annual road tax. The more powerful SLK 250 is actually more economical with its automatic gearbox, managing 42.8mpg and emissions of 153g/km. Even the V6-engined SLK 350 is respectably affordable to run, with 39.8mpg and 167g/km beating the entry-level Porsche Boxster, with figures of 35.8mpg and 183g/km.
The V8 petrol engined SLK 55 AMG is incredibly quick, but should still return a claimed 33.6mpg if you're very careful with the throttle, while emitting 195g/km, costing £265 per year in tax. The Porsche Boxster S returns 34.4mpg and emits 190g/km, placing it in the same tax band.
Every version of the Mercedes SLK is fitted with fuel-saving stop-start technology as standard, as well as an economy driving mode to encourage gentle driving.
Engines, drive & performance
All the engines in the Mercedes SLK range are powerful and responsive, with the diesel offering decent performance
While the Mercedes SLK is in many ways a direct competitor to the Porsche Boxster, the way in which it drives couldn’t be more different.
While the Boxster is direct, responsive and thrilling, the Mercedes SLK is smooth, comfortable and satisfying. If you are looking for a car to drive just for fun – or even take on the occasional track day – the Boxster will win every time. But, if you want a sports convertible to drive long distances in and perhaps to be your only car, the SLK is an attractive proposition.
To this end, the diesel automatic feels surprisingly well-suited to the SLK, offering a huge surge of overtaking power at motorway speeds. It has 201bhp and goes from 0-62mph in 6.7 seconds, one second quicker than the diesel Audi TT Roadster TDI.
The SLK 200 and 250 feel like they need to be worked harder than the diesel, but automatic versions deliver the 0-62mph sprint in 7.0 and 6.6 seconds respectively. The 302bhp SLK 350 has a big step-up in power and just beats the acceleration of the entry-level 2.7-litre Porsche Boxster, with 0-62mph in 5.6 seconds. But, it’s no match for the SLK 55 AMG with a huge 5.4-litre V8, 415bhp and taking only 4.6 seconds to reach the same benchmark. It’s something of a convertible hot rod and beats even the Porsche Boxster GTS for acceleration.
Interior & comfort
The Mercedes SLK is built for comfort, and can cover huge distances without breaking a sweat
The Mercedes SLK is less overtly sporty than the Porsche Boxster, with more of a focus on luxury, comfort and long-distance driving. It’s a strict two-seater, and you sit very low down with your legs stretched out in front of you, so it can take some getting used to. Our only complaint is the pedals, because they are slightly offset to the right.
All of the seats we’ve tried offer exceptional comfort and adjust electrically to improve your driving position. Airscarf is another a clever option designed to blow warm air on the back of your neck and is particularly welcome if you like driving with the roof down in winter. The Magic Sky Control is clever too, adjusting the transparency of the glass roof to let in more or less sunlight.
Unfortunately, visibility is not an SLK strong suit, partly because you sit so low and also because the windows are surrounded by thick door and roof pillars, making rear and over-the-shoulder views particularly poor. Use of the door mirrors and parking sensors is essential.
For a small sports car with large wheels, Mercedes has done a great job with the ride comfort, and it filters out most of the road's imperfections – preventing them from entering the cabin. Even larger potholes are kept from jarring occupants too much, although they’re still best avoided if possible.
Practicality & boot space
The Mercedes SLK has not been designed to be a practical car – but the boot is the largest in this class
While the Mercedes SLK will never be a practical car, it’s surprisingly capable for a small convertible. It can carry up to 335-litres of luggage, 19 litres more than a Ford Focus. But, this space is low and wide, so it’s better suited to soft bags than bulky suitcases – and shrinks to 225 litres if you want to put the roof down. Doing so also makes the boot opening much smaller and can make items hard to reach.
In comparison, the Audi TT Roadster is poor here, with just 250-litres of luggage space, while the Porsche Boxster has 280-litres split between its front and rear compartments. The BMW Z4 is the best of the bunch, at 310 litres, but still slightly behind the Merc.
Stowage spaces around the cabin include a reasonable glovebox, two cup holders behind the gearlever, tiny door pockets for your sunglasses and some cubbies and nets to hold small items. Space is tight, but there are more stowage places than you’ll find in the Boxster.
The Mercedes SLK comes with a tyre pressure monitoring system – to alert you of a puncture – and a tyre repair kit, with no option of a space saver spare wheel.
Reliability & safety
Build quality you can depend on and a range of safety equipment as standard on all Mercedes SLK models
The Mercedes brand was ranked ninth out of 33 manufacturers in the 2014 Driver Power customer satisfaction survey, dropping four places from 2013. It scored an impressive seventh for build quality though, so no matter which model you go for, it should feel solid and well made. The Mercedes SLK didn’t rank in the survey, but here have been no reports of widespread reliability issues.
Unfortunately the current SLK hasn’t been crash tested by Euro NCAP, but Mercedes has a legendary reputation for its safety technology and the SLK comes fully equipped with airbags and technology to help prevent skids and reduce stopping distances. It also features a system to detect drowsiness and alert you to take a break, while there’s even an active bonnet designed to pop up in a crash to help protect pedestrians by softening the impact.
The SLK is available with high-tech features including radar sensors to monitor your over-the-shoulder blind spots and alert you of traffic you may not have seen, as well as a warning if you follow traffic too closely. Pre-Safe can alert the driver if it detects the risk of a collision and improve braking response, or even brake automatically if the driver does not respond.
Price, value for money & options
The Mercedes SLK is an expensive car with pricey options
The Mercedes SLK is billed as a luxury model, so it certainly isn’t cheap and has a higher starting price than both the Audi TT Roadster and BMW Z4. However, this is somewhat made up for by its folding metal roof, where its rivals use a cheaper and less secure fabric version.
Available trim levels are simply called SLK and SLK AMG Sport, but don’t be fooled into thinking everything must be standard, this is just the starting point to your journey into the options catalogue.
A leather steering wheel, Bluetooth, digital radio, 17-inch alloy wheels and wind deflector are standard, while AMG Sport adds 18-inch wheels, tinted rear lights, enhanced brakes, sports suspension, trim highlights and steering wheel shift paddles for the automatic gearbox.
Airscarf is a worthwhile £395 option (only with heated and leather seats), while the roof with Magic Sky Control costs £1,995. Also for £1,995 the COMAND Online system has a seven-inch colour display with sat-nav and traffic information. Metallic paint colours cost between £645 and £1,125 and Mercedes even charges £50 for cup holders in the centre console.
The Mercedes SLK has a great reputation and it holds its value as well as the Audi TT Roadster and BMW Z4, but the Porsche Boxster retains even more of its list price, partly thanks to its greater exclusivity.