God speed dude.
Just know there were only two other Raptor supercharged Legacy's in the world; Stacy and Gino.
Note that I said 'were'. They both quickly realized what a complete waste of time, money, and parts it takes.
One: the ECU is not readable. It's not meant to be tuned in the traditional sense. The only person who tuned a supercharged Leg, or any Outback for that matter is Ed at XRT.
Two: the CVT is not the only factor, the poor brakes, suspension, and tires that are available for the Outback.
Three: you'll need new fuel rails, pump, cooler, injectors, and that's if the block doesn't warp. It wasn't built or design to take any amount of boost.
Why don't you visit us at the OutbackForums? We have literal Subaru engineers and Rocket Scientists. They can help you more.
Despite this, I hope you can get it working. If you do decide to do this you have my undivided attention and support. just wanted to inform you of what you're getting into. And honestly, the tuning is probably the easy part. Leave it to Ed, he's a legend.