Mazda announced that it will debut two new models at the Detroit auto show next month, one of which is a redesigned version of its RX-8 sports car that the company says has been "heavily revised." There aren't any photos of the RX-8 yet, but the automaker did release a teaser shot of the Furai concept sports car, which rides on a platform used in Mazda’s American Le Mans Series racing effort. The Furai is powered by a 450-hp rotary engine running on E100 ethanol.