Nope, actually there are quite a few 4* 120s out there running small gassers, and the ones I've seen fly very well. They are just like any other plane here that people overpower... if you build it strong enough, there's no problems. That's one good thing about the 120 size being offered only in kit form and not ARF; you can do all the strengthening and reinforcing at the time of the build and not have to worry about it later on.