RE: top flite corsair build questions
I would think that, if properly balanced, they would fly pretty much the same. Though, with the 120SP you would have more available power and torque at your disposal. It's nice to know you have some extra power available to get you out of trouble. I think there is some 10 oz. difference in the engine weights. I would just throw the big engine in and throttle back. Plus, spinning a big prop is the reason I bought the RCV anyway. Remember, these kits tend to build tail-heavy. My Corsair balanced with the big engine without adding any additional weight, and that was with Juice's prop hub and SoloProp blades (around 16 oz.). That extra engine weight will probably be of great value to you when you balance your plane.
Did you add extra ply to the firewall? If not, I would go back and do that just for piece of mind.