Alldatadiy.com is the best deal going. Something like $25 for the first annual subscription, then something like $15 to add annual subscriptions to additional vehicles. I have Alldata accounts on two Suburus, three Mercedes, and a Ford truck. They have paid for themselves and then some.
Subaru's service manual is several volumes thick. On some things it is great. On some (most?) things it is confusing, incomplete, and written in some dialect of English that is unfamilar to me. Lots of typos.