Performance
The line-up ranges from a 1.6 that should give bystanders plenty of time to see you cruise past, to a fast 2.0-litre turbo. The 1.8 will be the best seller, which although no ball of fire, is reasonably flexible. Vauxhall's first diesel convertible offers the best balance of pace and affordability.
Ride & handling
The Twintop may be an Astra without a fixed roof, but it's also an Astra without the on-road manners. There's a good deal of kickback through the steering, and the car's body flexes and wobbles over anything other than freshly laid Tarmac. Grip is reasonable, but the Twintop is easily knocked off line by bumps, even small ones.
Refinement
With the roof up, the Twintop is as taut and noise-resistant as a solid coupe. Take it down and, as long as the side windows are up, you're spared the sensation of sitting in a wind tunnel. Shakes and rattles are noticeable and the petrol engines sound boomy and gruff at all speeds. The diesel's not too rumbly, though.

Quality & reliability
Vauxhall says the roof mechanism has been tested 20,000 times for durability. It creaks and shudders a bit as it goes through its acrobatics, but the biggest frustration is the 26 seconds it all takes.

Safety & security
A strengthened windscreen surround and rear roll-over hoops (pop-up or fixed) are added to standard Astra safety features, and Vauxhall claims the body shell is 30% stiffer than the old convertible. There are front and side airbags but no curtains as in Volvo's rival C70, and stability control is optional. Naturally, with the roof in place, the Twin Top is more secure than any soft top.

Behind the wheel
The only real difference between the Twintop and the hatch is the impact on rearwards visibility with the roof up. Otherwise, you get the same multi-adjustable driving position and the same cluttered dash.

Space & practicality
Top up, the convertible's boot is more than a third bigger than the hatch's; top down, its capacity is halved, although with careful packing you can still get a fair amount in. There's an easy-lift feature which allows you to remove things without having to raise the whole roof. Rear headroom is poor and legroom is only adequate.
Equipment
Every version has an electric-folding roof and windows, a CD player and air-conditioning. The base 1.6 model has steel rather than alloy wheels; Sport trim and Design progressively add things such as remote audio controls, bigger alloy wheels, pop-up rather than fixed rear roll-over hoops and automatic lights and wipers