A better choice would be Impros. http://www.impros.com/
Dave at Impros used to work at Skat-Trak and he is the impeller guru. Not only does he repair impellers, he can blueprint and re-pitch it for you for your application.
if i ever get around to it dave said he would re pitch my skattrak swirl to keep the punch but make up for a mph or two also. Just have not got things torn down yet.