Mine has the leading edge lowered about 3/16 in. and is powered by OS .91 Surpass. Pull-pull rudder control. Magnum aluminum spinner. The servos were moved forward, rx and battery under the tank, no ballast. We fly at 6300 feet and the plane is strong for traditional scale-like aerobatics. I love the way it flies! I'd say if you keep the weight down by moving the radio forward, lightweight tailwheel, etc. and you're below 4000 feet the .70 will be enough. The plane isn't an Extra.