Vauxhall Astra

On sale now, the ί¿½19,995 drop-top certainly looks the part, sharing its bodykit and 17-inch wheels with the Coupί¿½ Turbo. Performance isn't far behind, either ί¿½ the 0-60mph time of 7.5 seconds is only half a second slower than that of the tin-top version, while the top speed of 151mph is identical.

We're normally big fans of the Astra Convertible, as the lowlier models offer plenty of refinement and practicality. But the combination of turbo power and 'rooflessness' has corrupted this version. Even at town centre speeds, the bigger wheels mean every bump sends a shudder through the cabin, making the car seem far less rigid than the non-Turbo models.

But the real problems arise when you unleash the power. As the turbo spools up, the tyres scrabble for grip and the steering wheel writhes in your hand. Trying to follow the intended line on a bumpy, wet road is as difficult as keeping hold of an excitable eel. This sensation will be familiar to Saab cabrio owners, but at least that car has the excuse of being based on an aged chassis and having to cope with more horsepower. It makes driving quickly a nerve-racking and worrying experience, and these aren't the sort of thrills we would be looking for in a fast drop-top.

We reckon the Astra Coupί¿½ Turbo is a far better bet for those wanting an exciting drive, while the normally aspirated Convertibles are more convincing packages for sun-seeking buyers.