I have an 04' so I don't have an open differential but I keep hearing about the Quaife differentail. Everyone has read the magazines saying it needs one but I guess I am just dumb when it comes to these because I don't know anything about them. I just know that it improves handling and powers both drive wheels under nearly all conditions. The Questions: Is it worth 1,300 or 1,400 to buy one? What is the BFD about them? And am I missing something about what they do?