I've been thinking about whether or not adding an inline electric water pump into the coolant pipes post-radiator would be a good idea. Some folks have theorized that the cooling issues a lot of people experience has to do with all the additional tubing and bends in the 818 cooling setup, and the factory Subaru water pump being under-sized for all that extra drag.

I haven't ever used an inline electric water pump so don't know much about them.... how much restriction they create when not running - would they need to be on all the time - if so, would it be hard on the pump for it to be running at all times even when the thermostat is closed, etc. What kind of lifespan do they have. etc.

Again, this would be to supplement the factory mechanical water pump.

Anyone given any thought into this or tried something out?