8.75 SureGrip , Is this Normal?

OK, I'm not sure...is that the LSD additive that is required when using standard gear oil? Because i am using an 85W-140 high quality transmission/diff oil that states it is for use in LSD's (In Australia, LSD is just the blanket term for Limited Slip Diff, applies to all makes of car). Or do I still need to add this friction modifier because it is a Sure-Grip?

Friction Modifier is required on top of gear oil. What friction modifier does, is actually kinda opposite of what you might think. It allows the clutches to slip some during normal driving conditions which allows longevity.