BW8512 is the Simer pump only part #. There is a part # that is a pump kit. It comes with pump, hose, extra impeller, etc...? Not sure what that part # is, but it might be cheaper to get the pump kit since it comes with the extra impeller rather than getting the pump and extra impeller separately. Check it out.
I second B.E. Atlas. I sent you their phone # in a reply to your WSR PM to me.