I have a 46 NX in my H-9 Cub. Horizon sent it to me as a replacement for the NT that came in it that wouldn't run correctly. It was a tuning nightmare, wouldn't run consistently no matter what I did. Different fuel, glow plugs, carb adjustments nothing worked. Horizon's Evolution repair department couldn't make it run right either and they replaced almost everything in it. So far the NX runs like a champ and has a lot of power. If I buy another 2 stroke it will probably be an Evolution. Horizon's customer service is first rate as well.