I have a great planes cub .25 on floats. It has the O.S. 25 with a pitts muffler. It flys great, and has more power than it knows what to do with. I keep it at 1/4 power to fly hands off. The floats are the stock .20 size from Great Planes. They work great, but, i would recommend pitting two water rudders on instead of the single. I fly it in the Florida bay, so it gets some chop. The real nice thing about this combination, is that it fits in the car!