A guide looks in from the entrance of a hall for a Louis Vuitton Voyages exhibition at the National Museum of China in Beijing on May 31. Luxury goods makers may boast familiarity with China, but the pace of change in the world's fastest-growing country still startles them. The world's biggest luxury market within five years has become a second home for brands that tap Chinese appetite for fast super sports cars, 10,000-euro ($14,060) handbags and diamonds.