Oops - just re-read this after I posted my reply. I have the ARF FS, engine choice doesn't change- but repair pics are not applicable.

I'm flying mine with an O.S. .25 FP, with the stock muffler. Changed the leadouts and bushed the LG hole with a piece of brass tubing CA'd in place. Balance is midway between leading edge and spar - makes for a stable basic stunt trainer.

The .25 has plenty of power and runs great. Put the stock tank on a .15 powered plane and am using a Hayes 3 oz plastic clunk tank on muffler pressure mounted on the inboard side to feed the .2 and get decent flight times -original is pretty small. Great plane, smooth and solid in flight.

Not quite so solid when you prang it into the ground, fuselage is pretty hollow. Broke mine off at the wing cutout, but the repair is easy and stronger than stock- or even a solid plank fuse. I posted a complete description and pics on Stuka Stunt if anyone is interested. Basically you drill 5/16" hole in the nose blocks, epoxy in some 1/4" od carbon rods, then glue them into the fuselage cavity with epoxy / micro ballon slurry.