Looking for some expert input as to engine selection. I started out with a Hangar 9 P-51 PTS and love it, removed all the training stuff and its a fast, fun flying plane. It has the evo .45 training system motor. This motor has been troublesome and is getting ready to be shipped back. When this motor runs good its fantastic but we just can't seem to keep it running properly so they are replacing it.

I purchased a Nexstar ARF for some leisurly flying and looking for a nice motor for it. I wanted to use something bigger than the .46 so I could later put it in another sports type plane. I was looking at the Magnum .52 but read that they needs some expert tweakage to run properly. I didn't want to spend a ton on this, the os 55 is double the competition. What would you folks recomend. I appreciate in advance your suggestions.