Porsche, one of the world’s leading sport car producers, said that China’s auto market has a huge potential for premium cars, the China Daily reported.   Upon unveiling its latest generation red 911 Turbo on Tuesday at the opening of the 2006 China (Guangzhou) International Automobile Exhibition, Porsche said that it would soon launch several other models including the new Boxster, 911 GT3, 911 GT3 RS and 911 Targa 4/4S for the Chinese market.   "Our strong presence at the expo and our strategy to promote our latest generation cars here indicates our ever-increasing focus on the Chinese market," said Mark Bishop, managing director of Porsche China, to the paper.   Porsche entered the Chinese market in 2001. It sold 857 cars in 2005, more than doubling the volume in 2004, wrote the paper.   In addition to the 14 existing centres, Porsche will open four more Porsche centres in Dongguan and Shenzhen in Guangdong Province, Haikou in Hainan Province, Harbin in Heilongjiang Province, as well as Changchun in Jilin Province, offering dealer services and tailor-made after-sales services.