New v used: Mazda MX-5 RF or Mercedes-Benz SLK?

New v used: Mazda MX-5 RF or Mercedes-Benz SLK?
New v used: Mazda MX-5 RF or Mercedes-Benz SLK?

Folding hard-top roadster buyers, should you spend £25k on a new Mazda or a used Mercedes?

The new Mazda MX-5 RF ‘Retractable Fastback’ is a marvel of lightweight engineering. It carries a snug folding hard-top targa-style roof that offers tin-lid security with open-roof pleasure, yet still weighs barely more than a tonne. It also costs less than £26k even in range-topping 2.0-litre Sport Nav guise. What’s not to like?

How about the fact you can get a two-year old version of the car that started the roadster craze for folding hard-tops, the Mercedes-Benz SLK, for less than that? And who wouldn’t rather run a Merc than a Mazda, particularly as this dealer’s SLK 200 AMG Sport model had covered just 3,700 miles as part of its £16k price cut from new to used. We borrowed one for the day to find out.

Side-by-side, it’s immediately apparent the SLK is a bigger car. And a heavier one: 350kg lardier than the Mazda. Good job it has a turbocharged 1.8-litre engine that delivers 23bhp more and a strong slice of extra torque – helping make it faster 0-62mph and, surprisingly, more economical too. Saying that, the MX-5 does win the open-top race, with its roof folding in 15 seconds compared to the SLK’s 20 seconds.

Mercedes-Benz SLK 200 AMG Sport

Price new: £36,710
Price now: £21,000
Engine: 1.8-litre, four-cylinder, turbo, petrol
Power: 181bhp
Torque: 199lb/ft
Gearbox: Seven-speed automatic
0-62mph: 7.0sec
Top speed: 147mph
Fuel economy: 43.5mpg
CO2/tax band: 151g/km, 27%

The extra class of the Merc badge shows inside, where there’s more soft-touch trim and snick-click switchgear. Occupants sit nice and low and the roof lowers fully rather than leaving the rear screen in place as with the Mazda. You do have to click a boot divider into place before it will go down, but even this only reduces capacity from 335 litres to 225 litres. The Mazda has just 127 litres…

The lightweight MX-5’s interior feels more paired down than the SLK, and there are some obvious omissions: no reach adjust for the steering, no glovebox, centre console infotainment dials positioned too far away. Taller drivers also felt they sat too high, which isn’t ideal for a racy little roadster. It was better equipped than the SLK though, and its touchscreen was bigger and more modern.

You’ll quickly fall in love with the Mazda’s 2.0-litre engine. Get the revs above 3,000rpm and it becomes vibrant and super-responsive, delivering a loud, sporty soundtrack that’s complemented by a brilliant short-throw six-speed gearbox. The SLK sounds dronier and more characterless, while its automatic gearbox isn’t anything like as pleasing.

Mazda MX-5 RF 160 Sport Nav

Price: £25,695
Engine: 2.0-litre, four-cylinder, petrol
Power: 158bhp
Torque: 148lb/ft
Gearbox: Six-speed manual
0-62mph: 7.4sec
Top speed: 134mph
Fuel economy: 40.9mpg
CO2/tax band: 161g/km, 29%

Both cars wear tuned-up suspension over standard. The AMG Sport SLK is lowered and stiffened, while the Mazda has a front strut brace and Bilstein dampers. It’s quickly obvious the MX-5 has a shorter wheelbase, because it bobs about more than the settled SLK. The Mercedes is steadfast in corners, handling comfortably and accurately.

The Mazda is far more thrilling though. Present are all the sensations filtered out of the Mercedes. Cornering is snappier, it’s more responsive, lighter steering is wonderfully precise and packed with feel. Sporty drivers will delight in the fact it has a limited-slip differential so they can showboat in their rear-drive sportscar on corner exits.

What a pity the MX-5 is so relatively unrefined with it, then. Roof down, there’s an unpleasantly boomy aerodynamic roar from behind your head which, combined with the drone from the engine, quickly becomes wearing. The SLK is in another class entirely, both roof up and down: no matter how good the Mazda is to drive, you’ll soon tire of it because of this uncouthness.

Which is why the SLK, against the odds, wins here. It’s not as thrilling, but it’s the car that hits the mark more closely at this price level. The MX-5 to go for is the much cheaper soft-top, which doesn’t suffer the flaws of this folding hard-top. If you really want a tin-top roadster, the secondhand Mercedes-Benz is where your money should go.

Top ten: PCP deals for under £400 a month

An executive saloon, an SUV, MPV – whatever you want, it’s available new for under £400pcmThe vast majority of new cars are

The Knowledge vs Uber vs sat-nav; which works best?

We tackle London’s chaotic streets three different ways, but which is the quickest?Tackling city streets in a car can be stressful, particularly

Do speed cameras really save lives?

Neil Thorpe, Newcastle University and Lee Fawcett, Newcastle UniversitySpeed cameras have been the focus of motorists’ anger and frustration

Buying used: Subaru Impreza WRX

How to navigate the multitude of models that make up the 2000-2007 Impreza WRXIf you like ample choice to pick from when buying a used performance