If a four stroke is your cup of tea. A nice 50 size engine is all you need. I reccomend Saito, I have and use them. Get an OS if you like. They are good engines as well. As for an OS 2 stroke I would say the 45 FX. Only because you can use it in later models. If your heart is set on an LA then the only real choice is the 46. I feel from what I have read the 40 is just not enough. Whatever engine you choose this plane will please you a lot.

Mark Shuman