I have found the following with my '01 9-3:
1) Although I may occasionally run 87 or 89 octane, I mostly use 91 or better. I have documented that I get 5-6% better gas mileage with the higher octane which is only 4-5% more expensive so either I win or its a wash. But it runs better on 91.
2) The sump only holds 4 liters (slightly over 4 quarts). A lot of us use a larger oil filter than stock in order to get more oil into the system. I use the NAPA Gold 1515. It allows me to get 5 quarts into the system. I also use Shell Rotella T 5W-40 synthetic oil. It is actually designed as an oil for turbo diesel trucks (but it does meet SAAB standards) and has a better detergent and additive package than a lot of auto only synth oils.
3) My local SAAB dealer was able to give me a print out that listed ALL recall and warranty work that had been done on the car.
Good Luck and good SAABing.