I would run a good performance pump like a Stewart or an Edelbrock Victor. Electrics can't match the coolant flow of these pumps (180 GPM vs. 35-55 GPM). Also, the parasitic loss from a Stewart or an Ebrock pump is only 2+ HP at 4000 rpm.
If you need a boost in flow at idle check into one of these:
http://www.stewartcomponents.com/htm...waterpumps.asp
Scott