They are same. Think AA makes a kit Novak also, there's another I can't remember at the moment. All are good stuff.
Question though, why do you need the 4:1? Extreme rock buggys? I have a buddy with the 6.5 kit in a sami, and another with a sami 4.5 kit. They just end up riding 3rd gear. And they run 35's and 3.73 gears. Too much reduction a lot of the time. I put mine in 1st and idle through obstacles with the occasional tap of the gas. They are almost too slow.. If you ever have a long loose hill climb its awful.
84 xj 350tbi, sm465, 203/205, 60/70. links and other junk.
what size sawzall blades does it take to fit 40's?