i have a question too..Im trying to mount my first motor and all the other ARF's i've got had the fire wall predrilled at the factory for the mount. Im building an Extra up that has a BOX type of fire wall at the front and a hole slightly at the top for the fuel tank to come through.. Do i mount my motor's crank in the middle of the hole in the fire wall or do i find the center of the whole fire wall and mount it there so it would be in the centre of the plane?