For 3D it will both help and hinder. It gives more thrust but loads the engine down. It delays the spool up and that can be a problem with 3D. I will slow down the plane and make it quieter due to lower RPM. 23x8 gives more prop wash across the surfaces. It does NOT cool the engine down more, just the opposite. It heats it up due to the higher load of the larger prop.

I fly mostly 3D with some IMAC stuff. I find that the 22x8 is the best prop for instant thrust on the light and powerful 50cc engines. If you have a pipe you may want to go to the 23x8 to keep the prop rip down.