I've heard good things about Yukon, also heard the FRPP diff is pretty good for the money. You can find the diff used for less, I believe they're stock in the 03-04 Cobra and Mach1 as well as Rangers, Explorers, and F150's.
It's the price that is the price, doesn't seem like a GOOD deal. But that is the around the price for all those parts. You can also get a used traction lock from a f150, yukon, and just rebuilt it a little, for less than 200$ Just a thought.