My speculation is it’s actually just the next revision of the 980 no spec difference but possibly cheaper to produce maybe has a higher load ceiling and it will make its way into all awd model 3s after they’re confident with its reliability in the LR AWD and/or when they run out of remaining 980 inventory
They've been using the 990 in cars for over a year now.
You think they had over a year worth of spare 980s taking up space?
And wouldn't putting a cheaper but JUST AS CAPABLE (or better) motor make more sense to put into the cheaper versions like the SR? But they don't do that either.