This is why any high wing airplane (all airplanes will respond to power changes with pitch changes) especially a cabin type which has the thrust line lower in the center of mass, normally will use a fair amount of down thrust (literally pointing the crankshaft at an angle downward).

What you are doing when trying to fly level at high power is forcing it beyond its trim speed. This will cause the airplane to become less stable in pitch and generally make you look bad just like a beginer.

Your airplane will never fly well and always look terrible in flight if you don,t pull the throttle back. Now having the extra power is indeed wonderfull and is very useful if you learn how to use it. Learn that throttle, never fly past the trim speed in level flight, use the power in your up lines and off the power on the downlines. You start to learn to use that throttle, then you will start impress your Buds. That airplane can do a great aerobatic routine.

There is nothing worse than some guy with a well powered trainer blasting around at full throttle trying to impress his friends but in reality he is just showing how little he knows. Don,t be that guy. learn to use the throttle

John