Just for grins, I ran the JBA 56 with its muffler, a Tower .46 muffler and the PowerBox from the OS .55AX. Interesting results.

Prop APC 12.25x3.75

JBA muffler 12,700
Tower muffler 12,300
OS .55AX PowerBox 12,300

The only other thing is the muffler weight
JBA muffler 5.5 oz
Tower muffler 3.8 oz
PowerBox 4.2 oz

The JBA muffler is pretty heavy.

No, I haven't tried it on the OS .55AX, yet.