I had one of these with an old Magnum .61 four stroke. It rocked with a 13X4 APC prop.

What Dealspeed is telling you about the Tower muffler is right on the mark. You will pick up over a thousand RPM's on a 12X4 APC prop with that muffler on 15% nitro. The APC 12.25X3.75W prop will give you a better mid range torque, however. I went with hi-toque mini servos all the way around and the plane barely weighed 4.5 pounds. The FX .46 is a much more responsive and powerful engine than my old .61 4S, especially with that $15 amazing muffler on it.

My only complaint with the plane was the translucent orance covering. It got hard to maintain aspect on it at some distance. A little solid colored trim in the right places, with different colors top and bottom did the trick.

Have fun with this plane, it is really a neat fun fly airplane and quite capable.