As I predicted before. They will become allies. It turned out and it happened in chapter 570. Yes. It is very long to wait. And finally Kyuubi agreed to become Naruto partner like Killer Bee and Hachibi. And most importantly, they become friends.
And whether Naruto will turn directly into Kyuubi or Kyuubi just give Naruto a large amount of chakra ?. But, i think, Naruto will transform to Kyuubi.
What is the reaction of Tobi if he know about this . Will he try to control the Kyuubi again.. Lets wait for the upcoming chapter next week.
Glad to see both of them working together