RE: two stroke or four stroke power?
saito 100 is great for overpowering 40 size planes but will not cut it for 3d on a 60 size plane. My uncle has a 100 on a pacific aeromodels 60 size edge 540 (7.8lbs) and hardly flys the plane because it is underpowered for any type of 3d, while I have a 125 on the ultra stick 60 and it is a blast to fly with power to do anything imaginable, even a vertical hand launch without any feer or effort. I have it with a 15x7 prop on 15 nitro with a 24 ounce tank mounted on the cg and no muffler (using a t on crankcase for pressure).
if you have decided on saito go for the 125 even if you have to save money to get it, it weighs only 3 ounces more than the 100 but has much more power.