THE Saab 900 Cabriolet has gone through another metamorphosis and has emerged as the Saab 900s Aero. The Aero is a little better equipped than the standard Cabriolet, and manages to be even more stylish, with sleek new body moulding giving the car its aerodynamic look and new name. And it is style that will sell this car. In terms of value for money, the Aero looks bad on paper. Anyone leafing through the brochures might easily dismiss the car as expensive and plain. The design is old and there is a distinct lack of the gizmos and trinkets that decorate the competition's wares. But the specification sheet does not do the Aero justice. Those who trouble to visit the Saab showroom and take a good look at the way the car is put together will see the Aero in a different light. The sight of the Aero's chunky form gleaming beneath a glossy layer of thick paint is enough to convince most that the spec sheet does not matter. This design is classic and no car maker has done better. The Italians build prettier convertibles and the Germans build more sporting rag-tops, but only Saab can make the open-top car, the most frivolous of vehicles, seem sensible. The way the door feels heavy and shuts with a solid thud suggests the car was built to last. The soft touch plastic of the controls and the way that the indicator stalk moves with a damped, positive motion give pleasure even before the ignition key is turned. It is worth taking a good look at the engine that fills the bay beneath the clam-shell bonnet, which opens up the whole front of the body for easy access. The motor looks as though it belongs in an aeroplane. It is a mass of beautiful castings and ducts and seems far bigger than the two-litre capacity would suggest. It makes the latest highly efficient Japanese two-litre four-cylinder power plants look puny in comparison. Just a glimpse of the rugged motor is enough to convince any potential Saab customer that he or she is buying some heavy engineering. But the Aero is not a clumsy and primitive beast. The entire design shows that tremendous thought has been applied to even the smallest aspects of driving, making the Aero one of the easiest of cars to drive. All the controls fall easily to hand, even if some features are idiosyncratic: the ignition switch down between the front seats takes a moment to get used to. There is a feeling of craftsmanship about the car. The craftsman's aim was to make the design efficient and no time has been wasted on useless decoration. The interior might have been too spartan if it were not for the wooden dashboard which comes as standard in the Aero, and which is a welcome touch of luxury. The steering and handling shows the directness and life that more modern cars have lost. There is a line of communication between the car's tyres and the driver's hands that is clear and honest and makes it easy to exploit the Aero's full performance. If there is a weakness in the car's driving ability, it is the three-speed automatic gearbox. The box performs perfectly well but would benefit from another ratio to help exploit the 145 brake horsepower of the turbo-charged, fuel-injected, 16-valve engine. A lot less money will buy a convertible car and many will prefer to spend less than half the Aero's $480,000 asking price on a Ford Capri soft-top. But the Saab has a quality feel that few other cars can match.