I put an OS 50sx on mine, I found the power much better then with my .46ax. If you can find an OS 50sx it is "the" combo to have in 2 stroke imho. The 50sx also has the same footprint as the 46ax so no modding required. Verticle is awesome.
My local hobby shop has an OS 50 SX on the shelf... They want a hundred (AU$) more for it than the 46 AX though... Which is a bit steep I think!
But might be worth thinking about if I can get them down a bit on the price.
I am keen to get hold of this ARF (Or maybe even the 60).
Hugh