Nothing has really gone wrong with the car, other that normal maintenance items.
Great car for us. It has been trouble free for the most part. The DI Cassette went out at 125,000 miles and cost $500 to fix. Someone else posted that it cost the almost $800, you should probably shop around to get a better price. I see a lot of oil sludge problems posted, and at 129,000 miles I have not had any issues with oil sludge. I change the oil every 5000 miles and use Mobile One Synthetic. I would definitely buy another Saab. We plan on keeping this one until 150,000 miles and then trading it in for another Saab. The routine maintenance it a bit pricey, but the first time this car saw the shop for a repair was at 125,000 miles for the DI Cassette. I definitely recommend the Saab.
I very much agree that the 1999 Saab 9-3 is a great car, and reliable. I also have one, 121k no major issues other than DI cassette and transmission mount. I change oil every 3-7,000 miles depending on if I've done mostly Hwy driving, and so far no sludge issue either. I absolutely LOVE my car, had it for a long time and plan on driving till the wheels fall off!