HOLDEN’S Astra, when it comes to scoring credibility points, just doesn’t seem to put a foot wrong.

The sedan, five and three-door hatch Astras, with their European combination of style and driving dynamics, have long reigned at the top of the small car class. Compared with the bulk of the small-car market, the little Holden is tangibly upmarket.

Then there’s the convertible.

Maybe it’s stretching the point, but the Bertone-designed Astra soft-top has been compared with Saab’s outgoing 9-3 convertible as a better-priced, almost equally desirable and prestigious alternative.

No-one would dispute the possibility of better dynamic behaviour, but there’s a sneaky feeling that even with its suspect mannerisms, the superseded Saab has a slight edge on the Holden in terms of street credibility.

But the Astra is certainly not lacking presence.

With its clean Euro look, plenty of standard equipment and the choice of normally aspirated or turbo power – and the benefits of one of the most extensive dealer chains in Australia - Holden’s only soft-top has caught the attention of buyers seeking a well-built, relatively spacious convertible that doesn’t cost the Earth.

With its only competition coming from a smattering of niche Euro importers, the Astra has soared to spectacular heights.

Driving the car, it’s not hard to understand why.

With the base Astra already forming a good platform from which to build, the package is well rounded in terms of what it gives for the money.

Just about everything you’d expect of a proper prestige convertible is there, from leather seats, climate-control air-conditioning, trip computer, one-switch power roof operation, and a few little embellishments separating it from the popular small car on which it is based.

The turbo version goes a little further with things like 17-inch alloy wheels, three-spoke leather-rimmed steering wheel, stainless steel scuff plates on the door sills, "sports" instrumentation and - wait for it - an oval stainless steel exhaust pipe extension.

The 2.0-litre turbo engine is a different animal to the all-alloy 2.2-litre engine fitted to both the normally aspirated convertible and the Holden Zafira people-mover.

It uses twin camshafts, 16 valves and a distributorless, coil-at-sparkplug direct ignition system, but it lacks both the alloy block and balance shafts employed in the bigger engine.

And, where the 2.2-litre and the smaller 1.8-litre engine also used in Astra have a torque-inducing long-stroke configuration, the turbo is exactly square in its bore-stroke dimensions.

With a turbo engine’s propensity for being torque-rich, this doesn’t place it at any disadvantage 250Nm from just 1950rpm and 147kW at 5600rpm are sufficient to haul the slightly heavier (something like 150kg over three-door Astra equivalents) convertible along quite rapidly.

Consistent with the turbo’s eager power production and therefore slightly sportier bent, there’s no auto option if you want one, it’s available in the 2.2-litre normally aspirated version.

The five-speed manual is essentially the same as the one used with the 2.2-litre engine, meaning a slightly closer set of ratios, mainly in the higher gears, that encourage a smooth flow of acceleration.

Inside, the Astra convertible is a pretty nice place to be, although - as with practically any four-seat soft-top - long-limbed people are probably best kept out of the back. There’s no fold-down backrest obviously, although a ski-port helps out when long items need to be stowed in the 330-litre boot. The spare in the convertible is a steel space-saver.

Up front, the seats are the same, more deeply sculpted "sports" design seen in the Astra SRi hatch and provide adjustable height and lumbar support – on both sides – although they are manually operated. The active head restraints seen on the top-of-the-line CDX Astra sedan and five-door hatch haven’t yet made it into the rest of the range.

Then sound system is a quality, 80-Watt six-speaker Blaupunkt with a single-disc CD player only. Like all but the most basic Astras, the turbo convertible provides steering wheel mounted sound system controls.

With a full-function trip computer, climate-control air-conditioning, cruise control, heated rear-view mirrors and electrically adjusted headlights, the Astra lacks very little, once again reinforcing its position as a quite classy contender.

There are some subtle giveaways though, that remind of its small car basis. The quality of the trim, on dash and doors, is clearly not at Saab levels, nor are the tangible, touchy-feely things like the switches, handles and general controls.

On the road it’s pretty good, though not entirely free of body movement as it trundles along - but a complete lack of flex in an open-top four-seater is a rare thing.

The roof-fold operation is one of those seemingly slow, flexing and contorting operations that leave you with either a clean, open-air exposure or a fully-lined, comfortable and well-sealed cocoon against the weather – complete with a demisting, glass rear window. The whole operation is conducted with the push of one switch, which is a handy, much-appreciated feature.

If you want a true sports car experience you’ll go for either the three-door hatch SRi - turbo or normally aspirated - but the heavier and less taut convertible still moves along swiftly and accurately.

The suspension – tuned by Lotus on all Astras – is quite absorbent although in sports tune it’s obviously less compliant.

The electro-hydraulic power steering (still quite rare on the market) finds a nice balance in providing enough weight to keep the car feeling secure on the open road, while making parking easy.

In keeping with its aspirations to appeal to a slightly upmarket audience the turbo convertible gets an electronic stability control system, all-disc braking (using larger discs on the front than other Astras) with four-channel ABS and traction control.

In terms of passive safety, there are four airbags (driver and passenger, dash and doors) front seatbelt pre-tensioners and force-limiters, and a pedal release system that helps to protect against lower limb injury in an accident.

A pretty appealing convertible, the Astra turbo. There’s certainly no shortage of style or performance and, as we said, the equipment levels leave few boxes un-ticked.

The fact that it’s also quite spacious and well put together helps explain why Australian soft-top buyers have embraced it so warmly.