Don, I appoligize if it seemed like I was trying to make one out to be better than the other. This was not my intention. We were discussing the weight that the Spacewalker needs inside its nose, and I was just pointing out options to consider when deciding what would be a good weight of engine to use, and what kind of power to expect if you either add weight with a certain engine, or lose weight. So please don't take my post as an O.S bash. I also own O.S engines, Magnum Engines, and Saito Engines. I have no problem with any of the ones I have. Another thing I was trying to point out was that it don't hurt to add a little dead weight if needed when using the Saito engine, because they are lighter, yet still have plenty of power. I am sure your O.S 120 does a great job in your Spacewalker, and again I appoligize if I sounded like I was bashing it.