Since you purchased the 40 size ultrastick I would really watch the weight. I know you have said you are already determined on a 4 stroke engine for this airplane. This is just my 2 cents. A two stroke is going to give your more punch. The 46 FX is great engine for this airplane. 50 SX would be a good option too. I really enjoyed 46 FX engine in this airplane. You really want to be mindful about weight because this airplane will do some really neat things if you don't get it too heavy. I used an 8 channel PPM Rx so I could set it up with all the neat things you will see in the book. I am assuming you will be setting your's up with flaps. If not then you won't need an 8 channel Rx. Reinforce the wing hold down area.