Mercedes SL65 AMG

The new flagship Mercedes SL65 AMG convertible has 18bhp more than the previous car, with its 6.0-litre V12 delivering 621bhp and an amazing 1,000Nm of torque, but it’s more efficient than before, as well as faster.

Engineers have reduced the weight by 170kg by using an aluminium body and other lightweight parts. This is great news, but despite the lighter shell and carbon fibre parts like the bootlid supports, the car still tips the scales at a substantial 1,950kg. Yet it does 0-62mph in a neck-snapping four seconds and 0-124mph in 11.8 seconds.

The hand-built engine has two turbos and is hooked up to a smooth-shifting seven-speed automatic – a first for the V12. Fold the metal hard-top – a fully automatic process that takes 20 seconds – and you can savour the thunderous soundtrack.

With the lid on, the car is as refined and comfortable as any coupé, with its massaging leather seats and great driving position, plus the Mercedes COMAND system takes care of navigation and chassis settings. There’s also a glass-roof option with the SLK’s colour-changing Magic Sky Control feature.

Yet most buyers will want to keep the roof down. Heated seats and Mercedes’ AirScarf system – which blows warm air on the back of your neck – make this realistic all year round.

With lots of grip, a superb stability system and strong brakes, the SL65 can be thrown around like a much smaller car. Plus, the new electric steering system weights up nicely and also contributes to improved economy – up from 20.2mpg in the old car to 24.4mpg.

The V8 version of this car – the SL63 AMG – offers slightly better throttle response, yet the V12 SL65 is an excellent grand tourer with its hurricane performance and cruising ability. Plus, it has the appeal of being the range-topping model. It’s not for the faint-hearted or the restrained – environmentally or financially – but is a great car.