Every single Saab mechanic I have talked to in my area has never dealt with a single timing chain problem UNLESS it was related to sludge or lubrication problems. While timing chains do stretch, they rarely wear to the point of where they need replacing. If you look closely at most of the cases of timing chain problems on this board, the people who are affected live either in areas of really cold climates or drive short distances while not fully warming up their engine. There are many factors involved such as oil quality, temperature, and maintenance, but the common factor in all these cases are that these Saabs spend their lives in states where it gets really cold. I personally have 172,000 miles on my 2.0 Turbo and the chain is silent. I am sure that unless you suspect sludge or other lubrication problems, your chain should be fine at 63K.