He may have had the early 9.5" like I have. You need a spacer if you have aftermarket coil over or for looks if you're on stock suspenstion. The new 9.5" will fit without spacers.
Edit: looks like he's running 10" square. It's optional for the spacers.
Let me get this straight... You are swapping out parts designed by some of the top engineers in the world because some guys sponsored by a company told you it's "better??" But when you ask the same guy about tracking, "oh no, I have a kid now" or "I just detailed my car." or "i just got new tires."