I'm a little confused. Why is it that you want to put a bigger engine on a plane that you already have trouble slowing down? As you stated, a cub is not intended to be a 3D plane and while the engine may be able to make it hover, the structure probably won't be able to handle it, for long at least. You don't give a lot of info about your approaches so it's really hard to recommend a solution to your landing problem, but I will guarantee that a bigger engine is not the solution.