Front or rear calipers on the 9-3 or the 900 can be rebuilt. Saab, and at least one aftermarket kit is available. In any case, you remove the calipers the same way as when the pads are being replaced. The fronts are usually easier to deal with than the rears.
Only difference is that most people remove or at least loosen the flexible brake line before the caliper comes off, because it helps to have the caliper steady to loosen the brake line union.
Many I ask why, Shizlets ? Your vehicle is not that old..
Are the pistons binding/hanging up ?
Some of these disk brake designs use delicate rubber seals to protect the machined pins on which the calipers slide. These seals should probably be renewed when the pads are done at around 50K miles...
To rebuild the calipers, examine the bores very carefully(wear and corrosion) - I think these last the life of the car - whatever that means...:cheesy:
I don't think we have to replace those on our cars. The 900 and 9-3 calipers are similar.
If the 9-3 has the same rubber insert, looking like a bushing for the guide bolt (slide pin), then I believe all you need to do is clean the part of the bolt that the caliper slides on thoroughly, and use some rubber-friendly lubricant on the surfaces where the metal makes contact with the rubber. I like to use a synthetic lube called Syl-Glide and NOT regular brake grease. There is a cap over the end of the slide bolt, so the bolt is protected fairly well if you service the brakes right.
I think a lot of the uneven pad wear and caliper piston binding on our cars is because when a brake shop replaced the pads, they cleaned everything well, but they may not have lubricated everything correctly. I am almost sure that's what happened to me at least once.