Hi,

I'm in the process of building one right now. The mods I'm making are as follows:

1) clipped one bay off the wings, but then added balsa block rounded off to each wingtip. (the wingspan didn't change, I just liked the rounded off look better. Purely a cosmetic change, but it does shave a fraction off the wing area and increase weight a tad.)
2) Sheeted the LE of the wings. There's no structural reason that you have to do this, I just like the look of a smooth sheeted leading edge.
3) bought a fiberglass cowl from Fiberglass specialties. Another cosmetic thing, but this cowl is awesome looking. I'll attach a pic.
4) Sheeting the turtle deck. Again, just cosmetic, I wanted the surfaces smooth.
5) extending and counterbalancing the elevator and rudder for better aerobatic performance.
6) adding Great Planes large size wheel pants.

I'm putting a TT 91fs in mine. I've been told that your 61fx is a great engine for this plane, too. In fact, someone made the comment on one post that his plane flew much better and hotter when he took off a 91 four stroke and installed a 61fx. So, I'd go with that engine if I already had it. It was a toss up for me, I almost bought a 61fx, but had never had a four stroke and wanted to hear that cool sound everyone talks about!

Good luck,
Heath