Jim,
I don't think cutting a hole in the box will be a big problem. It had to to do this to mine too in order to have room for the throttle and choke pushrods, and I think the hole is about 1" in diameter. Not a problem so far. Just make sure you pin the box with the recommended/supplied dowel.
I can only confirm what John says : The Eagle flies great and very predictive. I love mine.