I don't know where you read that a 46 was underpowered for this plane. Thsi plane was designed for a .40-.46 2 stroke, so the 46 is on the upper end of recommended engin sizes. I have an OS 46 AX engine on mine and I think it's a great combo. IMHO a 60 is going to way too much for it. Not considering the added weight, you also need to think about how much you're going to need to beef up the airframe for that much of a motor. I know that in this day and age everybody thinks that they need to shove the biggest motor they can find on a plane, but that's not always needed. I think that this plane flies great with the 46 AX on it, almost like it was made for that engine. It does everything I want it to do with no problems

That's just my 2 cents worth

Ken