certain things i need to make clear...the kyuubi though has been inside naruto and has been helping naruto in battles, i would consider using it's power unfair. There is a difference between using kyuubi as a SUMMON and using it as a sealed bijuu. for the second case, the user gains direct access to the bijuu's huge chakra reserves and powers and uses them as his own. But when used as a summon such advantages are not there and the user himself is vulnerable. In BM naruto gets to use the entire chakra of kyuubi as his own which obviously is a plus point for him. So yes, naruto has some unfair advantages even if he has learnt to control the kyuubi's chakra...because admit it or not, kyuubi is a different source of raw chakra and power which is given to naruto but doesn't belong to him and he gets direct access to that power as if it were his own.
As for sasuke, well, his techniques are all due to his own chakra, whether it be amaterasu, susanoo or anything.....except for kirin for which he uses natural lightning. And those who think naruto can easily defeat sasuke...let me ask you something...naruto is physically fast and has insane raw speed thanks to kyuubi's chakra.....but will it be that effective against sasuke?? Not really because activation of susanoo is instantaneous and if sasuke covers that armor with amaterasu flames then he will be untouchable....even with his speed naruto cannot touch him as long as he is covered by susanoo+amaterasu. So i really don't think naruto can defeat sasuke that easily. In my opinion both have a 50-50 chance of winning.
