ORIGINAL: Yann

Oh god !!! that was the question I didn't want you to ask...
On the fuse: Changed the rudder setup.
Changed the thrust pipe for a wren pipe.
Removed (easily) most of the formers, to change them. plywood was not up to my standards.
Changed the turbine beams to suit the small footprint of my wren.
Wings: Custom made new springs for oleos (absolutely necessary)
Changed O-ring brakes for regular rim brakes. I could not brake evenly with stock ones.
Changed most of the servo pockets as some of those parts were missing from my kit. So I dit it all over, my way.
Modified flaps setup as well, to allow more deflection.
Modified main gear doors my own way. Still don't understand how FEJ wanted me to do it.
That's it for the most important parts. There is more, but that was more on the cosmetic side...