I built one a very long time ago. As for the kit it is straight forward and easy to build. I used an OS .25 for power, still have the engine. The plane is fantastic to fly and with the .25 it was very fast. I don't recall anything about the CG so I can't say if the .40 FS will be a problem. Power wise it will be fine. Right now I fly with a friend that just bought the eflite TC and I enjoy flying it too. At $150.00 dollars I'm just glad I didn't have to pay for it but it's one of the better ARFs I have ever seen. Very scale looking and built well.