The Somethin' Extra is a step up in aerobatic performance from the 4*40. The proportionately larger control surfaces and wing planform with shorter coupling to the tailplanes makes the aircraft MUCH more responsive.

I've seen the Somethin Extra matched with an Irvine 53 and it was a VERY good match. A good pilot can take that combination and compete with almost any 3D "Fun-Fly" aircraft. (and do bette than the Fun Fly plane at some things...)

The only problem spot to watch for when building the Somethin Extra is the alignment dowel for the wings. Be CERTAIN that its glued in well. (and some people recommend replacing the dowel with a harder material) If the dowel shifts to the side, (or breaks) one wing will pivot around the main tube, and you'll have NO control of the aircraft.

The rubber band on "J" hooks for wing retension is just fine. It takes very little tension to keep the wing from sliding outward. Some people use a zip tie instead of the rubber band, just to be sure the wing won't shift... but its not really necessary.