In 1999 Audi produced 15 models – in 2009 this number has swelled to 29. The Audi A5 Cabriolet is the latest in an almighty product offensive.

It’s a replacement for the Audi A4 Cabriolet, which has proved a huge success among buyers looking for four seat saloon car sensibilities, with the options to catch some rays on sunny days.

Stuart Milne travelled to Monte Carlo to sample the new Audi A5 Cabriolet.

The Audi A4 Cabriolet was a recipe for success – style, space, ability and the build quality Audi is famous for.

But for some, the looks could have benefitted from a little more pizzazz. And that's where the Audi A5 Cabriolet steps in, replacing the A4.

Class-leading looks

The standard Audi A5 coupe is a handsome car, with its restrained curves and purposeful haunches – but the Cabriolet simply eclipses it.

With its main rivals being the sober Mercedes CLK and look-at-me BMW 3 Series Cabriolet, the A5 drop top surely has an A-list look about it – and that's likely to please Audi's image-conscious buyers.

It bucks the current trend for folding metal roofs, instead employing a cloth roof that can fold in 15 seconds at speeds up to 31mph – and should the remote Comfort Key be specified, drivers can even operate it standing next to the car.

Refinement is an Audi hallmark, and its engineers have developed an Acoustic Hood, which is said to make the cabin almost as quiet as the A5's coupe brother.

A wind deflector, which folds flat into the boot floor when not in use, eliminates the majority of wind buffeting too.

But perhaps the biggest news is a start-stop system which cuts the engine when the car is stationary – it’s a first for the A5, and works as well as the best on the market. It will find its way into cars later in 2009, but early cars will be sold without.

Another new feature on the A5 Cabriolet is a neck-level heating system – similar to the Airscarf system found on the Mercedes SLK – which maximises the roof-down opportunities for British buyers. Heat reflecting leather seats are also available and are said to be up to 20 degrees cooler than standard leather after a day in the sun.

Petrol and diesel power

From launch, Audi will offer three engines; two petrol and one diesel. The petrols include the 211PS 2-litre TFSI and 265PS 3.2 V6 TFSI, while the diesel is a 240PS 3-litre. Further engines will be introduced later in the year.

The hot Audi S5 Cabriolet is also available with a supercharged 3-litre V6, which develops 333PS, and is reviewed separately.

There's a choice of gearboxes, which is limited depending on engine, and whether two-wheel drive or Quattro four-wheel drive is specified. The line up includes a six-speed manual, eight-speed 'Multitronic' auto and seven-speed 'S Tronic'. The latter is similar to Volkswagen's fast-shifting DSG gearbox, while the Multitronic is a CVT 'box that constantly varies the gear ratios, and is among the best on the market.

Through the winding roads around Monaco, the Audi A5 Cabriolet is almost as accomplished as its Coupe sibling. The steering has plenty of weight and is direct, if not offering the most natural feel through the wheel. What is not in doubt is the levels of grip offered by both the two and four-wheel drive versions. It’s possible to pitch the car into bends faster than you'd thought possible, and the car remains flat throughout.

Clever technology enables power to be channelled between the rear wheels on Quattro models and allows the outside rear wheel more torque to 'push' the car through bends quickly and safely.

The ride is firm but not jarring, and Audi offers two active suspension packages to tailor the ride and handling from comfort to sport modes. There's a little of the shake most cabriolet's suffer from, but it doesn't detract from an excellent driving experience.

Excellent power and economy

Audi claims the A5 Cabriolet's performance and running costs better the equivalent BMW 3 Series Cabriolet and Mercedes CLK. New technology means the engines have remarkably low CO2 emissions, and none bar the hot S5 model, tips over the 200g/km mark.

Fuel consumption is in excess of 40mpg for the manual 2-litre petrol and 3-litre diesel, but the 3.2 petrol dips to the low thirties.

All engines cover the 0-62mph mark in around seven seconds, and will all travel to at least twice the UK motorway limit. But there's not always a sense of that performance, particularly with the exceptionally refined 3.2.

We also sampled the 2-litre TDi (on sale in September) and it proved refined and punchy.

The Audi A4 Cabriolet scored well for interior space, comfortably seating four. Unfortunately the rear of the A5 Cabriolet suffers at the hands of style, and while there proved enough space for a five foot, ten inch passenger, an hours' journey is really the maximum.

It's better news in the boot, where the boot measures 380 or 320-litres depending on whether the roof is up; and can increase to 750 when the 50/50 split rear seats are folded.

The Audi A5 Cabriolet should sell by the boatload, thanks to its great looks, but scratch beneath the surface, and it reveals itself as a fine grand tourer.

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Check out this video review of the Audi A5 Coupe...