I would imagine anyone approving such a mod, would want to well and truly cover their backside.
Many years ago, I read of an Aussie, flying over a remote sheep/cattle station, spotting an aircraft way below him, close to the ground, flying somewhat erratically. He noted the Reg.
On investigation, it transpired the odd aircraft had been written-off a considerable time prior. The remote station-owner had bought the remains, patched it up and nailed a Rover 3.5 litre V8 car engine and radiator on the front.
It flew, but would you have put your name to it's airworthiness?
sometimes, people have to be saved from themselves.
I'm sure some conversions are very simple, others present difficulty such as W&B totally out, too much torque, not enough power........Yes, pen-pushers can be frustrating, but from what I've heard of the LAA , they do a magnificent job for very modest costs, compared to the CAA.........just think if you'd wanted to modify a similar machine on a C of A..............then count your blessings.
not, and never have been a member, not a pilot, just stood back, looking at the big picture.