There are many changes between the two. The older one was about 2 pound lighter, One piece wing, Leading edge extensions at the root of the wing and optional leading edge droops, everything was accessed from the bottom. The new one was based on the maverick platform, plug in wings, removable canopy, removable tailcone, no lex's, different airfoil. My old viper is still flying and I feel it is easy to fly once you get used to it. The old one, of course was more of a craftsmans kit and was a more intense build. I would love to find another old kit to build.