I have the Extra Special and originally put a Webra .40 blackhead on it. It flew the plane well, and would actually hover it (barely).

I have since switched to an O.S. .46fx and its a different airplane. I have never had a plane this overpowered, and I kinda like it.

I think the average person would be more than satisfied with the .42 on this plane. I'm just not one of them.