I had an ARF Streak a number of years back. Flew with an LA25 and a stock muffler. It was a mild, controllable, flier. Never checked the cg. Probably the combination weighed more than the Fox. Does the Fox have a muffler? Stick one on, if not. Probably not enough weight in the nose. Just a thought. Is the push rod flexing at all? Must use the guide to keep it rigid. One nice thing about Streaks, is that they can fly well fairly slow. I'd put an LA25 in the nose of your next one. (Or if you can find it, an equivalent FP). The stock nose is weak, eventually they break off. I imagine the extra vibes of the Fox 35 would quicken the process. ARF Streaks can be no muss no fuss. A great way into comp stunt. I've seen lots of them in Beginner. Flew myself out of Beginner using one. Even when the fues is rebuilt to overcome the inherent weakness of the nose construction (not much wood there, hollow) it's easy to get them in the air.