You beat me to the punch Stomper.Most of the mods can be purchased directly from Gene @TBM & the rest is a very careful lightning of the fuselage in general..The radical mod was moving the wing back 2" to change the center of lift to offset What the designer did to allow the use of such a heavy engine as the Zenoah 80.This airplane will hover at just above idle & will accelerate straight up faster than most planes can in straight & level flight.Like anything that is built for max performance it AINT cheap but you get what you pay for.Bottom line is "LIGHT IS RIGHT".Does the term "WING LOADING" ring any bells?