Inside & Out:
From the outside there are few giveaways that this is a diesel-powered roadster, save for some very discreet badges. That means you get a slightly effeminate two-seat roadster with a pleasing front, but rather bulbous rear end.
Only the rev-counter gives the game away inside too, and the rest of the cabin will be familiar to any other SLK driver. In fact, much of the switchgear is shared with other Mercedes models too, and some of it is surprisingly rather cheap to the touch.
The optional Airscarf, sending heated air from the headrests to your neck, is a worthwhile and well-thought out addition though. And the folding hard-top operates smoothly and efficiently, even leaving a decent amount of boot space when stowed.
Ride & Handling:
It's very rear-biased this car, leaving you feeling sat out over the back axle, the long bonnet in front you pivoting from just behind your hips. Turn-in is certainly sharp, the feeling accentuated by the above, but the light steering is short on feedback.
On a racetrack you'd likely feel the extra weight of the diesel lump over the nose, translating into slightly more understeer, but even at higher speeds on public roads the SLK 250 CDI feels nimble and agile. The suspension can be a little firm though, and the extra weight of the folding roof can make itself felt in the car's body roll through the bends.
And the thick pillars, canted at a shallow angle, mean that taller drivers will find their heads close to the trim, which can be uncomfortably claustrophobic.
Engine & Transmission:
If ever there was a car that made sense on paper, this diesel-powered SLK is it. A glance at the figures reveals a 0-62mph time of only 6.7 seconds and a top speed of 151mph, yet combined economy of 56.5mpg and a lowly 132g/km of CO
2 emissions - there's just no arguing with that. And certainly on the road this SLK 250 CDI performs strongly, as you'd expect with 500Nm worth of shove at only 1,600rpm.
However, there is no getting away from
that noise. There's a familiar diesel clatter at start up and low revs, and if you extend the four-cylinder unit beyond 3,500rpm it becomes intrusive. It is refined at cruising speeds though. We just can't help feeling this is a concept flawed by its execution - a six-cylinder diesel would have worked much better.
And the sensation isn't helped by the narrow power band, which, along with the noise, is at odds with a roadster's purpose. Still, the seven-speed automatic gearbox is smooth and there are paddles behind the wheel for manual control. Frankly the SLK 250 CDI should not be dismissed because of its diesel engine, but for some, no matter how efficient or powerful, it just won't suit.
Equipment, Economy & Value for Money:
It has to be said that our test car didn't feel particularly special, which is surprising considering its optional equipment list ran to over £12,000 and the final price was nearer £50,000. You don't have to get carried away with ticking the boxes either - the Airscarf is £395, heated seats £330 and satnav £1,995.
Still, it's the only true two-seat diesel roadster currently on sale at the moment, and the low emissions and high economy guarantee palatable running costs - especially when performance is taken into account.
