I think a 46 size engine will be to small.
I have the 540 and it has a 4 stroke .91 and it still could use a little more power.
If I had my choice I would have gone with a Saito 100 (reluctantly), only because Magnum doesn't make a 100.
Seagull makes a good plane for the price, I really like flying mine and it looks soooo nice too!