A good sport flying model plane is one that will take anything you can throw at it. I flew a Midwest .20 Stik with a Fox .40 and later a Webra .50 for many years and did everything I could to break the rubberbands that held on the wing. That plane held up to tons of abuse and finally had to be dismantled and thrown in the burn barrel due to fuel soaking and general uglyness. If the plane isn't built too heavy in all the wrong areas and just heavy enough in all the right areas, you shouldn't have to worry about how you fly it. Ever seen a pylon racer run the course? We're talking about a 3.5 pound plane with 2 horsepower. If any of the design wisdom and engineering that these planes have could trickle down to the ARF sport level designs, you wouldn't see as many structural failures or be led to believe that structural failures are your fault for flying with gusto.