I'm flying one of these for fun now, and keeping the trim pieces attached is almost a full time job. It's a very good flying trainer, however, and suprisingly aerobatic for a flat-bottomed wing trainer.

An O.S. .40 LA engine is a very good fit for this trainer, the ARF builds out surprisingly light and the .40 LA has enough power to haul it around well. It's also lightweight enough that the plane should balance well. I found mine to be rather noseheavy with a .46 FX up front, even with my NiCd battery way, way back in the tail section of the fuselage.