For more than two decades, Sweden's Volvo Cars has coveted a U.S. production plant to help restore it as a leading European import brand. The past 10 years have seen Volvo's sale by Ford Motor Co., its 2010 acquisition by China's Zhejiang Geely, and now eight years later, the official opening last week of a $1.1 billion production plant in Ridgeville, S.C., that eventually will have 4,000 workers.