New /old style water pump impellers

[03GC]

Just bought a new waterpump on Ebay for my 03 Grand Cherokee, and it has the older style stamped steel impeller. Does any one know how much better the new full round phenolic impeller (1999-04 GC or 2001?-2006 TJ) cools? Hesco's pump has an alumninum version of the late pump impeller(Hesco came first from what I have read) .
Any thoughts? I may be sending this pump back .
Paul

[Plechtan]

The Hesco style pump takes less HP, try posting on the Hesco site, they will probably tell you how much less.

[03GC]

Not really concerned about the HP or torque benefits, mostly the difference in cooling. The improved impeller is supposed to increase flow between 10-20%. Is there a problem with strokers getting hot ? Does this greater flow make a hot running stroker run cooler? The Hesco pump is about 3 times the price of a replacement pump, but it looks like rebuilt pumps and the new pumps from GMB use a 5 blade steel impeller.
Thanks for any input,
Paul

[Exos]

I know the OEM style replacement water pump I bought from Canadian Tire is "hi-flow" and even with a 195 degrees thermostat, I run cooler than the old engine. It's a Prestone water pump.