actually, he is as fast as sasuke, because of sasuke's limitations. sasuke's teleportation is instant, but it works within a limited area. naruto is extremely fast, therefore within that rang he will be just as fast as sasuke. but if sasuke's had no rang or at least a bigger one, than there actually would be a speed difference. but as it stands now, due to circumstances, naruto is faster because he doesn't have to teleport than attack. naruto has the advantage of it being one motion but sasuke has to do 2, that being teleporting than attacking. naruto can do both at the same time. for instance say they had to go 100 yards, but sasuke can only go 20 yards at a given teleport. naruto would get to that 100 yard mark before sasuke. why? because naruto is just as fast as sasuke within that 20 yard distance and all naruto has to do is make one quick dart across the field; sasuke on the other hand, has to do multiple teleports, which he has to activate his rennigan ability and see where he is going of course. thus naruto doesnt have any speed loss while sasuke has several in that instance. hope that explains it.