I am trouble shooting trying to get my Z520 and Evinrude ETEC 250HO to run like it used to. I have the new M2 gear case and lost 3-4 mph. I can only run 68-69 fully loaded with a Fury 25 or 26 right now and the prop specialist at Lake Fork suggested a Power Tech 4 blade RKR4. He said most people with my same setup have seen great results. I am just skeptical about buying an aftermarket prop because they are not cheap! Anybody have anything good/bad to say about Power Tech props??