We've got a special update about some of the new vehicles debuting at this week's Detroit auto show. Porsche returns to the event for the first time in four years and plans to show a racing version of the 918 Spyder. Speaking of race cars, Cadillac will debut the racing version of the CTS-V Coupe. Chevy will show its replacement for the Aveo called the Sonic. All that and more, plus a look at the new Kia Optima Turbo.