$36 per hp isn't too bad.
Positives - cooling the engine with it not running, better cooling at low rpms or at idle, +10 hp
Negatives - does not flow as much as stock at higher rpms, risk of motor failure as well as seal failure.
Think about it. It'* a centrifugal pump turning at a constant 1800 rpm (I think) with a larger impeller than stock.
The stock pump runs at engine rpm.....1000 - 6000 rpm
Even with the larger impeller, it will not outflow the factory pump at speeds over say 3500 rpm.
Would I do it again. I don't know cause I only just installed one.
Let you know next year.