G'day
Kostas for a 40 size plane the 46 ax does give you unlimited vertical power. Speaking from experience I had one in a 40 size PC9 and just kept on going up and up and up and up and up. Provided that you treat the engine properly the 46 ax wil give you the performance that you need.

Also a fella at my local club had one of the GP extra 300s 40 size with a 46 ax and it would hover and pull out easily.[8D]