I used this, as its what Subaru recommended to me on the phone.
Worst mistake of my ownership so far. Its viscosity both cold and hot are wayyyy above most 80/90 spec gearbox lubes.
Shifts were notchy, and i felt like I had to row slowly. It would grind reverse when cold starting.
After a LOT of research and phone calls to the various companies asking for additive lists, I settled on:
Penrite Pro Gear 75-90.
GL5, copper safe, Mil spec approved, PAO\ESTER base, and its about half as thick (correctly in spec!), and has better shear values, can be used straight pour in LSD's.
Shifts became much smoother, grinding when cold starting is eliminated, I can shift MUCH quicker, and a nice bonus is it didnt smell much
It meets all the specs subaru requires afaik, wasnt much more expensive, and I have nothing bad to say about it. (few mates are running it now too, not in subarus, with great results).
Cant speak highly enough of it.
Of course, as with cars, your milage may vary
Your advice is in no way wrong; Subaru recommended the Castrol Multi\Universal,and it clearly let me drive the car fine.
Just that I think I might have found something new (hopefully better?) for everyone to try