I had a dazzler with on OS 40SF in the nose. For those of you who are relatively new, that would be the equivalent to a 40fx. All I can say is this plane likes to be slightly tail heavy, at least if you want to get all the wild potential out of it. If you use any engine heavier than an OS 40la, be prepared to either place the servos in the rear of the plane or add 2 oz or so to the tail to get the right cg. My first flight was without any tailweight and the plane felt very heavy, especially in turns and on landing, the tail weight corrected this but it still landed hot. I"m building an uproar now and I"ll locate the servos in the back so as not to add weight excessive weight for the new OS 46fx motor I'm putting on it.