I am new and have just learned to fly. But I'm going to put my two cents in anyway. I have a LT-40 (I Built the kit not the ARF) with the OS 46LA. I will give you the same advise my club members and LHS gave me. If your going with the OS engine stick with the LA. The engine is easy to start (Even in the 30 degree weather I've been flying in so far) and it flies just perfect at half throttle. 1.2hp is just fine. Save the cash from the FX on your 2nd plane.