I have the Ford Contour dual electric fans. Low speed(resistor in the shroud) for thermal switch, high speed for A/C. Built into a shroud that covers over 95% of my radiator. Work very well, even in the 100+ degree weather we get here in the summer. On low speed, I can feel air flowing out from under the car at the back bumper. These fans move A LOT of air.
The trick to electric fans is wiring them correctly, with thermal switches and relays, not directly off the battery with 18ga. wire. Most people burn up fans by not using big enough wire, and by having the fans always on, instead of cycling with a thermal switch.
Edit: If you don't know how to wire electric fans, use the stock fan and shroud. It will definitely do the job.