The third generation of Mercedes‘ pioneering tin-top convertible is the best yet, certainly from a driving and a looks perspective.

While maybe not as pretty as its predecessor, the more muscular new SLK is also a big step forward in driving enjoyment and particularly efficiency, with both the SLK 200 and SLK 250 models well under the 160g/km capital allowance point.

The SLK 250 driven here is a 204hp 1.8-litre model coming in at 153g/km and an average 42.8mpg. There is a 184hp SLK 200 that’s £4220 cheaper and 2g/km more efficient, but given that the 204hp version occasionally feels like it could use more power, the entry model is probably not as recommendable.

The feel for more power comes from a chassis that’s more sporting than previous SLK models, and is actually a decent match for the Audi TT Convertible and BMW Z4, both of which come with considerably higher emissions. The rival TT sits at 168g/km and the Z4 192g/km, although a 184hp sub-160g/km Z4 is about to launch.

But the Mercedes needs those efficiency advantages, as the SLK is quickly clawed back on price. At not much under £40,000, it’s around £7000 more than the equivalent TT roadster, which admittedly has a fabric rather than metal roof, and it’s £3500 up on the suitable Z4. The Audi is, though, also the only one of the trio not to benefit from a standard leather interior.

As well as a dominant efficiency position, the new SLK is significantly more practical than its German rivals, thanks to a 335-litre boot that’s large enough to easily fit in a weekend’s luggage, as long as you don’t also want to drop the roof that eats into boot space by housing the folded car top out of sight.

The SLK is a better car to drive and less feminine to look at than its predecessor, which will be either a good or bad thing depending on your viewpoint. But the most desirable of the two-seat convertibles at this level is also the least attainable, with a high purchase price meaning a comfortable win for the Audi TT Roadster at 73.4p per mile against the SLK’s 83.1p, although the SLK’s better depreciation and efficiency place it in front of the Z4 23i for whole-life costs.

Mercedes SLK 250 Blue Eff.
P11D price £39,425
Model price range £29,980-£44,225
Residual value 41.2%
Depreciation £23,200
Fuel £8666
Service, Maintenance
and Repair
£2766
Vehicle Excise Duty £495
National Insurance £3428
Cost per mile 83.1p
Fuel consumption 42.8mpg
CO2 (tax) 153g/km (20%)
BIK 20/40% per month £131/£263
Service interval 1yr/15,500mls
Insurance (1-50) group 45
Warranty 3yrs/unlimited mls
Boot space min/max 225/335 litres
Engine size/power 1796cc/204hp
Top speed/0-62mph 151mph/6.6secs
On sale August 2011
Verdict The most efficient
way to glamorous
top-down motoring
Score 7/10