I have a 2000 SL2- I've not had to replace the actual power window regulators (the motor/drive mechanism) but did have to pull apart the passenger rear door to replace the plastic clip that holds the window to the regulator when it broke (a common occurance according to the SaturnFan forums). That wasn't all that difficult to do, and I don't remember the regulator being altogether too buried. The biggest concern is likely going to be getting the inner door panels off without breaking anything- they are REALLY tricky at times!
I strongly recommend in general having the Chilton's or Haynes repair manuals for the car, they're a great reference when you want to do something and have lots of good information about fluids & regular maintenance too- though they don't outright state what most of us know about the S-series which is that you always have to add more oil!
