Amsoil and G80?
 

Since no one seems to have ran Schaeffer with a G80 LSD, has anyone ran Amsoil SVG 75w90 with a G80 LSD? Did you need additional LSD modifier?

I haven't personally. You can run the SV no problem. Their gears lubes come with modifier already in it, but it won't hurt a thing if you want to add more to it.