No I'm talking about an OS 91 two stroke. Works great on the sig senior. No problems at all. My instuctor was hovering the senior with it. I bought the exact same engine for my sig. I also bought a twelve ounce fuel tank instead of the ten ounce it comes with. My instuctors senior had quite a few miles on it with the 91.

I don't know how you can compare the two planes even with the same engine on them. All you have to do is look at the control surfaces of the Nexstar and then look at the control surfaces on the sig senior. There is no comparing them whether your running the the same engine on both, or totally different ones.