I hear ya, I'm running a 13x6 & turning 12,400. It pulls that 6 pound extra like it weighs nothing, I put a pull pull rudder & 2 hs81mg servo's in the tail & 2 on the ailerons, got spoilerons & flaperons programmed & it's way cool. I can only imagine what a light funfly would be like with the ys63 in it.

Gil