With my decision to switch to the 650, the only backtracking I brought on myself was the rudder. While I know that it flies the same as the 601XL rudder, I like the looks of the new style and I wanted to have my plane look like a 650 by all outward appearances. My cost to come up with the new rudder was $75 for sheet aluminum, $40 for the composite tip rib and $9.50 for the new upper rudder hinge. Oh, did I mention 28.75 hours of my life? It's pretty clear I'm working for minimum wage on this project!