Aside from dehead mastering, I clipped the restricting tabs inside side arm/torso assembly so they can swing all the way down putting tread on the ground. Removed the grey hip kibble so legs can rotate all the way up. Thigh flaps cover shoulder bit so it is a cleaner f-zero/jet mode. Also canon can mount as thruster as another member found or on one side for off blanced destruction.
You can do almost the same thing with fan-modes, so no permanent changes need to be done, especially for the cannon on the rear as a thruster. Nice alt mode, though.