The Buick Riviera, a stunning concept car designed to showcase Buick's new global design direction, made its global debut today at Auto Shanghai 2007. The gullwing Riviera concept coupe was developed with global design input by the Pan Asia Technical Automotive Center (PATAC) in China, a design and engineering joint venture between General Motors and Shanghai Automotive Industry Corporation (SAIC). The Riviera was introduced today by Rick Wagoner, GM Chairman and CEO, and Hu Maoyuan, SAIC...