There are four direct-injection petrol models, from four-cylinder 320i (168bhp) to the straight-six, 3.0-litre twin-turbo 335i. This range-toping unit is smooth and cultured in its impressive power delivery, yet potentially economical. The diesel engines include the strong 320d, 325d and 330d, all providing massive mid-range pulling power.

BMW has managed to fit a folding metal roof, add 160 kilos of body stiffening and maintain most of the responsiveness and feel expected of a 3 Series. The suspension is a little softer than the coupe's, which marginally changes the ride-and-handling balance, but not in any seriously detrimental way.

With the roof in place you can see why BMW wanted a metal-roof coupe-cabriolet in place of a soft-top: the latest 3 Series convertible is as hushed and weatherproof as a saloon. Even with the car fully open (roof and windows down), it's acceptably draught- and din-free for anyone in the front seats, and road- and engine noise never become intrusive.

Prices aren't cheap and you won't get much of a discount, even if you buy online. However, strong residuals mean you'll get plenty back when you sell. Running costs are competitive, too. The engines are frugal despite their power, and low emissions keep company car tax bills down.

Mechanically, BMWs rarely give trouble, so even though some of the engines are appearing for the first time, there's no need to fear problems. Electrical glitches are not unknown in BMWs, though, and the new hood mechanism is unproven. Build quality - both the choice of materials and the way they are put together - is exemplary.

A coupe-cabriolet is always going to provide a sterner test for thieves than a soft-top - one of the reasons why they are now so popular. Safety provisions are all you'd expect from BMW, with stability control, self-drying anti-lock brakes, two front airbags, big body-and-head side airbags and automatically activated roll-over hoops fitted.

The folding metal roof does wonders for visibility in the 3 Series convertible. Compared with a traditional cloth roof you can see more of what's behind. It's hard to fault the adjustability of the driving position or the control layout, too, which will include BMW's iDrive - now much improved over the original version - if you choose the sat-nav option.

BMW says this is a no-compromise car - that's not true. To ensure it looks good from the outside (no high-rise or elongated boot compared with some coupe-cabrios), luggage and rear-seat space suffer. Still, the rear backrest folds down to provide useful extra storage space, and there's even a through-hatch (a coupe-cabrio first) for skis and golf bags.

Every model has a healthy standard specification, including niceties such as automatic lights and wipers, electric seat adjustment, rear parking sensors and automatic air conditioning. However, there's plenty more you can add, such as leather trim that reflects much of the sun's heat.