If you set up your homie 25cc right and I mean you can get 7200-7500 rpm with an APC 18x8 wide blade prop, and I get that outa my homies with a muffler and large carb both got from Pete at wacker engines.com as my only mods, then you can expect great performance outa most 120 size planes. Lanier Stinger, sig 4-star120, any Dynaflight giant scale and Cubs would also be great fliers.
25cc of any gas motor wont turn any 120 size plane into a 3D aircraft but for honest, cheap power that you can fly on season after season and use the money saved for better airborne equipment the ryobie 31cc and homelite 25cc and 30cc just are hard to beat. Piper