Hey Dan fancy going sideway's do we ?????
There is no button or standard option to turn it off
possibly you could cut some wire or something i don't know
But remember your Subaru is permanent 4wd so any "spirited"
circular or sideway's displays will blow your diff eventually.
So why do you want to turn it off ????
If it's to achive 4 wheel drift on your favourite right hand corner,
a little left then hard right and hard on acceleration