I read about 2-3 years ago that the hot-ticket for the WJ was to cut it for a berkley impeller. I believe that a shop in orange county was doing it for about $1200 at the time. If I'm not mistaken (and I don't want to start a fight) they said that it would make it perform better than any pump berkley and jacuzzi ever made. I read it in HB, if anyone remembers.