Converting an engine to burn ethanol is a relatively simple matter of replacing some hoses and seals at the factory, but the Saab BioPower engine is the first to use the corn-based gas to actually enhance performance. Available in Sweden in the 9-5 sedan and wagon–and possibly later in 9-3 models–it generates 148 horsepower on pure gasoline, but when it sniffs ethanol, it cranks up the turbocharger’s boost pressure (ethanol can handle higher pressure better than gas) to lift output to 184 horsepower. How’s that for an eco-friendly incentive?