How to replace 2002 Saab 9-5 ,2 L, 4 Cyl, turbo engine air filter? Thanks!?

It is just in front of the penger side wheel, at the very bottom of the engine compartment. Get under the car, and have a Torx screwdriver (there should be one next to the spare tire in the trunk if you don't already have one). If you have the Aero front spoiler, you may have to undo some screws to move it out of the way to get enough access. Looking under the car, it is a pretty big circley-shaped plastic housing, probably 8 or 10 inches across, held on by (IIRC) three torx screws. Undo those and lower the plastic and the air filter should fall right out with it. Just stuff the new one back in there and bolt everything back up, and you should be good to go!