General Motors Corp. has captured a spot among the top three automakers in a respected quality rating. In a new survey by J.D. Power and Associates, GM passed Nissan to rank third among big automakers behind Toyota and Honda.GM trailed Nissan by 1 point, regarded as statistically insignificant, last May. But the ranking is symbolically important to a U.S. auto industry that has been playing catch-up in quality to their Japanese competitors for two decades.GM was helped by its Saturn division, which climbed to No. 4 from No. 13 among brands. "I believe it's the first time since the IQS study began (15 years ago) that GM has been in the top three," said Tom Kowaleski, GM spokesman for product and brand communications.