For Not far behind the V8 version for outright pace, and running costs aren't quite as steep.
Against Can't get near the diesel on running costs, and it won't go anywhere near as far on a tank of fuel.
What Car? says
The one to have if petrol power is a must, but if you have an open mind, we'd strongly recommend the diesel.
What Car? readers say
View the whole BMW 6 Series Convertible range
Target Price team says:
With most models (apart from the range-topping M6), you have two trims to choose from. We recommend SE, because it comes with all the luxury toys you need. MSport trim adds plenty to the price, but only cosmetic revisions to the car. On both, standard kit includes Drive Dynamic Control, which lets you choose between four driving modes ranging from Comfort to Sport+, and tailors the steering, gearbox and throttle accordingly. Optional Adaptive Drive also adjusts the suspension according to your selected mode.
You choose between four engines. The petrols include a 3.0-litre turbo known as the 640i, and a 4.4-litre twin-turbocharged V8 badged 650i, both driven through an eight-speed automatic gearbox. Both are hugely quick, but so is the 640d, which has a 3.0-litre turbodiesel. It also has lower running costs and a superior touring range, and that’s why it’s our favourite. For buyers who want the ultimate 6-Series drophead, though, the M6 version has an incredible 552bhp.