China's auto sector is booming. The top four names in the Auto/Truck-Original Equipment group, which includes U.S. and foreign companies, are all based in China. This column on Monday featured Wonder Auto Technology (WATG), a maker of alternators, starters and other electrical components. Today let's scrutinize China Automotive Systems (CAAS), a small-cap company based in China's Hubei Province that makes power steering systems and other parts,