I have a Tiger and here's the only areas I deviated from the plans, per some tips from some guys here on RCU. I added triangle reinforcement to the Wing Hold Downs in the Fuselage. I didn't put in the wing tips, I just capped off the last rid with some 1/16" balsa. I used a small piece of triangle stock on both sides of the verticle fin really as cosmetic more than stength. Other than those things I follwed the iplans to a "T". The best thing you can do with this plane is to build it as lite as you possibly can. There's no need to "beef" anything up really, as the plane will fly down and grease onto the runway with a little landing practice. Almost better than a trainer plane. From a performance stand-point I'm getting alot of fun out of this plane with an O.S. 61 FX with an 11x7.5 Prop. Mentioned earlier, it's not unlimited verticle but it will climb pretty high going staright up. Snap rolls are very crisp and fast with a little extra throw on the control surfaces. If I was to build one again other than what I mentioned I would only add some stock to the back of the Rudder and Elevator. What I mean by that is a piece of maybe 1/4"x1" balsa glued right to the trailing edge of these control surfaces and then shaped like the ones you would see on a Great Planes Sky Bolt. This is a really good 2nd Air Plane with great potential to introduce you to some advanced aerobatics. It flies really well, and it seems in my experience with a few other's Tigers, the lighter it's built the better it flies.