Will,
The Weiand water pump works great! And since it doesn't have the bypass circuit you can
use a regular Windsor thermostat too. FWIW, it's the same waterpump that PIM sells too.
No need to modify it for the bypass circuit either, as far as I can tell.
http://www.banzairunnerpantera.com/updates_thermostat.htm
Cheers!
Garth