That’s nowhere in Subaru’s literature nor in the body of evidence in 20+ years of manual Subarus that I’ve seen. The STi has an adjustable center, and I believe can only be set to 35:65 to 50:50. The Forester, Impreza, Legacy/Outback manuals from what I’ve read and what Fenske’s had are “locked” at 50:50; the front diff is open so the spinning tire gets the power, and only the Legacy/Outback with LSD are any better in the rear.Manuals with the viscous coupling are not fixed 50:50. The default split is 50:50, and the coupling can go up to around 70:30 or 30:70 depending on which axle has slip.
If you’ve got definitive proof that it’s not 50/50 I’d like to see it, because the locked split was always what was of interest to me.