RE: OS .91FX for Four-Star 60
You might want to consider the OS91 surpass. I fly my 4*60 with one and it is a great combination. As indicated, the 4* is not a 3D plane, and the surpass gives it plenty of power for most aerobatics. Some have even taken off the outside bay on the wings to get greater roll rates, but I fly mine stock and enjoy it for what it is.