2 strokes to 4 huh well I have owned both and my 3rd plane I put my first 4 stroke in I was 22 years old at the time. I had no issues rule of thumb 2 stroke = high speed high rpms 4 strokes= tons of torque less speed lower rpms. Spooling time in a 2 stroke is slower than a 4 and you wont get the pulling power from a 2 you will with a 4. I am partial to 4's I have owned quite a few and I am not by any means a "gear head" I know the basics and consider myself to be more a geek on the physics side of planes props and flight characteristics. I have never had an issue with any of mine. I had OS, Enya, YS and Saito all 4 strokes. Dont get me wrong I have never had any issues with my 2's either i just prefer 4's. Good Luck. Try a 4 stroke you may never go back