I built mine stock I guess except for the dual aileron servos and with a Saito 72 in the nose weighing right at 7 lbs and flew like a dream that is till the battery or switch went out on me on the 7th flight, ouch! I'm planning to build another just like it. Am finishing an Astro Hog right now and as soon as I put the chain saw away I want to put the Hog Bipe on the board. What engine you planning for yours?