Props for the best performance

Was researching these Sharrow props as they promised the highest performance and fuel savings of all props available. Not sure yet, at $5k for each prop that's a lot to swallow. If the savings were there it would be easier, but I believe after speaking with other experts that the gains may be a bit exaggerated. I do believe it is more efficient since airboat propellers and airplane wings have been updated in recent years to allow the 'wing' to be more efficient by eliminating the tips. Hmmm.