Diff cases went together slick as snot. I even left the shims as they were in my hand done diff cases. I think the diffs spin freer inside the cases. I could REALLY make them spin free if I remove a few more shims, but I prefer the diffs with tight tolerances. Personal preference. SInce these have not been run yet-Im sure after a couple packs they will free-up even more-they always do!!!
I am not looking for spin time-just a very free feeling and these have it.