I went with the FMS carbon rebuild kit and although it wasn't really a difficult job, it was pretty time consuming (and messy). The S-spring trick with the hose clamps worked very well and I cannot image how else you would get the thing in there.
I was never a fan of the one wheel wonder . Good job mate. I somehow managed to get the S-spring in there without a clamp, but we'll see if I can do it again pretty soon.
Ford Racing M-4700-C is the part number, I paid $117 shipped from Summit.
The only other items you need to complete the install are:
Some Ford friction modifier to soak the clutches in (you will also need a 4oz bottle to put in the diff UNLESS you use synthetic LS oil which already has the necessary modifiers in it) The modifier used to soak the clutches is supposed to be discarded.