Personally, I would use the Redline.
We used to distribute the stuff until RL started price gouging. We're currently trying Royal Purple and Amsoil, both of which are very good alternatives.
Aside: I've been taking apart diffs recently. I did about 8 E34 units earlier today. In the units with redline, the fluid "sticks" to the components. Anything else runs off. For Fritz, the extra cost in RL is worth it in my opinion.
best, whit