I am beginning a build of a new Phoenix Funstar MKII. I will be using HS 425 BB Servos all the way around so the airframe will already be a little heavier built than designed. Should I go with the OS 46 AX, or 55AX?

Thank you for any replies!

Do you already have these 2 engines that you are limiting your choice to only these? Have you considered a 4-stroke engine? A 4-stroke engine is great for 3D flying. But if it is only these 2 engines that you would consider, I would personally pay the extra $10 and get the 55. Although it is heavier, it can swing a 3D prop like the APC 12.25x3.75 and give 3D performance that you might be looking for.