When was the last time you got excited about a Saab? Precisely. Which is why the GM-owned Swedish car maker has developed the Aero X, a 400bhp, four-wheel-drive supercar with a DSG-style gearbox and an aircraft-style canopy. It was one of the head-turners of the Geneva motor show and it's hoped that it will become the catalyst for turning Saab around over the next few years.