That is an interesting kit, but are you wanting a posi rear? I would suggest limited slip if you are mainly on the road; or a selectable locker. I'm getting ready for a regear and have chosen the Eaton Detroit Truetrac. Please be careful when purchasing complete kits like that; you may not get the quality that you'd expect, which isn't a good compromise for the convenience.SvtLdr suggested Revolution Gear & Axle, but what about other manufacturers like Alloy USA, Yukon and Motive Gear.
I fount an interresting Kit on Ebay: https://www.ebay.com/itm/2737519141...d=link&campid=5337789113&toolid=20001&mkevt=1
Ebay takes all the hassle with the custumer duty and taxes from me, but I didn´t find any Revolution Gear kit with international shipping on ebay.
The Grip Pro should have the Partnumbers GT443027 and GT443527.