This is probably on here already, but Hexmods has a great tutorial with lots of pics for installation of this good kit, but as far as I have researched is only for limited years of the 5EAT.
Hope the link to this product is o.k. with this forum. This product works well, but it is a bit of an install without a lot of diy experience.
https://transgo.com/product-details/subaru-5eat-reprogramming-kit/