Before you start replacing motors, which may or may not be the problem, try other things. The front windows in particular have a tendency to bind up mechanically. Next time the window stops working, try taking the door apart, remove the 3 bolts holding the motor in, and take out the motor. You'll see the tension release, and putting the motor back in will allow things to work again. While the door panel is off, lubing the regulator mechanism well, with a good silicone based grease could very well solve the problem.
Unless things changed after 2000, the motors are the same for each door. The regulator mechanism is different.
Black 2000 SSEi, Silverstar Headlights, Angel Eyes fogs, 3rd brake light overlay, hi-flo cat, drilled 180 degree thermostat, Intense FWI, PCM, shift kit, and 3.4 Pulley. Solid front mount.