I agree with deice above.
Every show I go to is packed with "plastic fantastic" planes, and I always have a good nose around them. They all have a Rotax up front, a Garmin 296 in the middle of the panel, and the better ones have one of those "miniature G1000" panels. Very slick.
But I can see how they get the performance. They strip out all they can - like a Morgan car - and use much thinner control fixtures and linkages. Yesterday I was at a show in Greece and the flaps on some Czech machine rotated on pins which were M4 bolts. That is about 1/3 of the shear strength of a TB20 flat hinge. The control linkages are straight off some hang glider. Basically it is hang glider technology but with some skin to make it look like a real plane.
And they do break - plenty often enough.
The aluminium (where they don't use a painted fabric) is so thin you could almost poke a finger through it.
One day, if this ever becomes legal, I might build myself a fully composite carbon/kevlar plane with a turbine up front. Fully IFR of course. FL300 ceiling, 1400kg MTOW giving a +3000ft/min climb, 250kt TAS at FL250. Rated to +/-10G.