First off I really hope Sasuke joins the good guys again. If that happens and he helps win the war he may go back to the leaf. Sasuke and Naruto will still fight. I want them both to fight each other over the title of Chunin. Both are still Genin. If it happens that way then I believe that Sasuke will win. Not becuase one is stronger or weaker than the other but because of something Naruto said very early in the first series. He said he will become Hokage even if he is a Genin for life.