Yellow Yota

Get two little bottles of Dana Spicer limited slip friction modifier. If you use synthetic oil, make sure you get the one that is compatible. The best price I could find it was at my local Ford dealership. Had it in stock, too. It was labeled as a Motorcraft product, but it was obviously the same prouct as the Dana Spicer stuff. The numbers were even the same.
Even if someone tells you to only use one, put two in. Mag-Hytec pans hold more oil. Drive in figure 8's about 10-15 times to get it worked into the clutches.

And yes. Limited slip, Anti-spin, LSD, Posi, and a handful of other terms all mean LIMITED SLIP DIFFERENTIAL.