The lightest way to reinforce the wing is with some carbon fiber tape under the wing
skins. My Illusion has nothing added just the wing skins, although the wings are glassed
and painted instead of monokote, so I'm sure the fiberglass added enough reinforcement..
The retracts are mounted on flat plywood plates just epoxied to the wing cores, never had
a problem. My MVVS was rear exhaust so I just cut a channel in the belly and made a
pipe tunnel out of 1/16" balsa with fiberglass cloth over it, real easy.

To Dan from Carolina Custom Aircraft,
The Illusion is a great flying airplane but it was designed to fly fast and it does that, real well.
If your serious about competing in the new pattern events it IS too fast, I've done it and it's very
difficult to stay inside the 60 deg box at high speed and it doesn't fly that well at slow speeds, it
wasn't meant to. I like it but there are many new designs better suited to todays pattern.

tommy s