BMW 320Cd Convertible

Fitting an oil-burner in a car without the soundproofing that comes with a metal roof is a brave move. But BMW's accountants have decided that there is money to be made from a diesel cabriolet. So do their sums add up?

There's no doubt about what's powering the 320Cd at low speeds with the roof down. But head above 30mph and wind noise drowns out the rattle from the engine. With the hood in place, though, the 3-Series is as quiet as its tin-topped sibling, while performance is barely affected by the car's extra weight.

However, part of the fun of wind-in-the-hair motoring is being able to hear the exhaust note - and the 320Cd's is not great. Prices start at ΂£28,350, and for about ΂£1,000 more, you could be revelling in the aural delights of the six-cylinder 325Ci. So is there any point to this model? Yes, but only if your annual mileage is high, or you're a company driver who wants to enjoy alfresco motoring. Order now, and your car will be delivered in the spring. If you're a sun-loving accountant, it all makes sense...