The very first official details of Audi's replacement for the venerable A4 Cabriolet were released late last night and as predicted, the new open-topped car is based on the A5 coupé, not the new A4 saloon as its predecessor was.

Unlike its biggest competitor, the BMW 3 Series Convertible, the new A5 Cabriolet employs a traditional fabric soft-top. Audi cites weight and packaging as convincing arguments for sticking with a soft-top while others utilise a folding hardtop. The A5's roof retracts in 15 seconds and closes up again in 17, all at the touch of a single button and at speeds up to 31mph.

The A5 Cabriolet retains the four-seat layout of its coupé sibling and includes a rear seat back that allows full access to the boot. Though down on load carrying ability in comparison to the coupé, the new Cabriolet's roof-down 320-litre load space betters that of its BMW rival and the A5 also retains a flat rear deck for an elegant top-down appearance.

Audi will offer a wide range of engine and transmission options from launch. Entry-level models are front-wheel drive with a six-speed manual gearbox, though quattro four-wheel drive, a seven-speed, dual-clutch S tronic transmission and a Multitronic CVT will be optional across the line-up - dependant on model. The 1.8-litre TFSI engine will be the cheapest petrol option, though it may not come to the UK initially, with the A5 range to be topped off by a 3.2-litre V6 option. A version of the 2.0-litre TFSI unit will be offered, while the 3.0-litre V6 turbodiesel will also be available. We expect Audi's 2.0-litre common-rail turbodiesel to also be offered in the future.

Enthusiasts will be keen to hear more about the new S5 Cabriolet, as it features the all-new supercharged V6 that recently made its debut in the Audi S4. Maximum power output is 329bhp, while peak torque of 325lb.ft is produced between 2,900- and 5,300rpm. Quattro four-wheel drive is standard in the S5 Cabriolet and 0-62mph is despatched in 5.6 seconds. Top speed is limited to 155mph. Thanks in part to direct injection, combined economy is 29.4mpg.

Audi will also offer the new sport differential on the A5 and S5 Cabriolets, as part of the Drive Select function, allowing the driver to customise his car's dynamics.

It's expected that Audi will give the A5 Cabriolet its world debut at the Geneva Show in March, with sales starting soon after. UK pricing has yet to be announced, but expect entry-level models to cost a fraction under £30,000, with the S5 Cabriolet at £42,000.

Shane O' Donoghue - 3 Dec 2008