Did you try greasing/rebuilding them as described in the FAQ? If the windows are just slow, they can be sped up by greasing the tracks and regulator assembly with bearing grease or lithium grease. If the regulator is clicking, grease may help, but you'll likely have to replace it or take it apart and see what's wrong. I bought a new regulator/motor assembly from the mazda dealer for $300 as mine was damaged. Try greasing them and see if they loosen up first.
In my opinion, these window regulators are not of the best design. Even with a brand new regulator and motor, the window still takes 5-6 seconds to go up/down.
