The factory uses and recommends 75W90 GL-5. The reason for using Redline 75W90 NS is that the NS does not have the friction modifiers that their regular 75W90 does. The friction modifiers will not allow the synchros in the trans to work properly.
As for the limited-slip ours are sealed viscous-type units and the lubricant does not affect them.
If I am not mistaken the 75W90NS can be used in the rear differential as well as the trans/center.