Mine runs fine with a OS 46 FX w/Tower Muffler. It's a pattern trainer, not a speed or 3D plane. I run the recommended throws with the CG at the rear end of the recommended range. There's a big difference in handling with the CG at the front or rear of the recommended range. It's hard to hold knife-edge with CG forward.

The best thing about it is: It's neutral It goes where you point it. I can run a 11x5 for thrust and good strong uplines or a 10x7 for speed. Either way, it takes some time to slow down when you want to land.

It's very stable with no snap tendancies.