The DP flys just fine on a YS120. It will hover, do some 3D depending on throws. IMHO any plane that will hover is certainly adequately powered unless wild 3D is your taste. A 140 is only needed for ballistic vertical performance. A 120 on a Goldberg is a little much, although I know many people use them quite successfully. Remember that the Goldberg is a 9ish pound plane, give or take. The DP should come in around 11ish. The Goldberg was designed as a 60 size two stroke plane, the DP as a 120. Patrick designed them both.