Electric fans replacing OEM can be a dodgy proposition. If I were doing it, I'd probably go with one of the two fans in this order:
1. Ford Taurus 16" electric (this fan has a 400-450 watt motor judging from its amperage draw)
2. SPAL model 30102113 (265 watt motor)
There's no such thing as a free lunch with fans, and those manufacturers that are claiming 3000 cfm with only a 10 amp draw are full of BS. Judge a fan by its motor wattage if you can get it.
I wouldn't replace a working OEM fan setup with anything less than a true 3000 CFM fan.