Alright, trimmed about 1.5" off the wing extensions (leaving about 1.5"), put the dime back in the nose, and took her out.

Amazing! That's what I think of the quad now. It flies straight, it flys fast, and it turns with control. You can still overdo the turn, but that's actually pretty fun if you get it up a ways and and pull out of the spiral. I think I'm done with tweaking, and about ready to call this one good.

So final (sort of) specs for the Aero Ace Quad:

-Extra motors placed about .5" in from leading edge of top wing (blades stick out from the side a bit), with the other components installed as described earlier.
-Lower wings removed, upper wings extended 1.5" with some upward dihedral angle (can use the wings from the donor plane).
-Front of nose reinforced with fiber-reinforced tape, dime or similar weight in the nose.