RE: Alpha 60 with bigger engine
I would just leave the Evolution 60 in it. A trainer gains absolutely nothing from being overpowered. In fact, it can actually have a negative impact. When a plane has less power the pilot needs to learn to fly the wing of the plane instead of relying on power to get out of trouble. If you learn to fly a plane with less power you'll wind up being a better pilot in the long run.
Ken