A rigid body structure - almost three times stiffer than that of its predecessor - and an all-new suspension layout are key features of Saab's new 9-3 convertible, unveiled at the Geneva motor show on Tuesday.

The new convertible includes a supplementary so-called "ring of steel" reinforcement linking the front, rear and side structures, helping to compensate for the loss of structural rigidity due to the absence of a roof and also improving ride refinement, handling and crash-impact resistance.

Compared to its predecessor, the new car gains 2.0 inches (51 mm) in overall width and 2.8 inches (71 mm) in wheelbase. Despite reduced front and rear overhangs, the overall length of 182.5 inches remains the same as the previous model.

The all-aluminium, four-cylinder 2.0-litre engine, configured for 175- or 210-hp, is 33 pounds lighter than its predecessor and is smoother, quieter and more compact. It has a four-valve cylinder head, maintenance-free chain-driven camshafts, counter-rotating balancer shafts, a dual-mass flywheel and an integrated oil cooler.

Two manual transmissions are available, depending on the engine. A five-speed manual is standard with the 175-hp 2.0t engine. A new, compact 6-speed manual gearbox, capable of handling exceptionally high torque loadings, is standard equipment on the 210-hp 2.0T variants. A new "smart" five-speed automatic transmission is optional, including Saab Sentronic, a sequential manual gear shift, adaptive to both the driver and road conditions.

Crash impact resistance benefits from a series of new structural and occupant protection measures. Safety features for front seats include new seatbelts integrated into the seat frames, adaptive dual front airbags, two-stage side-impact airbags designed to offer protection for both the torso and the head, and Saab Active Head Restraints (SAHR), proven to be effective in helping to prevent neck injury during rear-end collisions.

Although rollovers are comparatively rare events, the consequences are quite serious and Saab has installed an active protection system in the new 9-3 Convertible. Its DynaCage concept combines pop-up rear roll bars, front seatbelt pre-tensioning and substantial reinforcement of the A-pillars to help provide an integrated protection system.

The "one-touch" soft-top operation requires no manual involvement beyond pressing a button. The roof is hydraulically-powered, with automatic self-latching to the header rail, and deploys fully in just 20 seconds while the engine is running. This is partly achieved by the Convertible's tonneau, which has a unique two-step cycle, being completely raised horizontally and then moved rearwards, parallel to the top of the boot.

Another innovation is a more practical feature: raising the roof automatically raises the capacity of the boot. The CargoSET (Self-Expanding Trunk) directly links the soft-top's rearmost hinge mechanism to the flexible, "accordion" storage well in the boot. When the roof is in position, the well is fully retracted, releasing useful storage space.

The new convertible will be built in a dedicated new production facility at Magna Steyr Fahrzeugtechnik, near Graz, Austria.