I'm not so sure that those electric water pumps are a good idea, considering where I have seen most of them mounted. Placing a pump in the lower radiator hose, IMHO, would provide absolutely no coolant circulation until the thermostat opens. Given that, I would think that you would observe localized overheating prior to the opening of the thermostat. That can't be good for an engine, especially an aluminum one.
In addition to that, I don't think you would get any cabin heat from the heater core until the thermostat opened either (in winter). That could really suck...
