There is a threaded recovery point somewhere on the front bumper. It is pretty stout, I have snatched multiple rally cars using that. the ring is in the toolkit somewhere. The best option for the back is a trailer hitch. if you want to get really fancy, unbolt the factory tiedowns and have someone fab up a real recovery point using the original attachment points and a bar between them to spread the load.
Primitive racing has the best skid plate available right now with an extention to cover the trans. add one to the rear diff, and for rocker protection, pull the factory plastic rockers, and carbon/kevlar them for 5-6 layers that will get you through most everything. you can also add pin style jack points and use a converted Radflow hydraulic jack or an exhaust jack.
If you are going to go crazy with it I would suggest plating the strut mounting points. every once in a while I have seen them break through under severe rally duty. The only other underbody that you may want would protect the floors. the rally cars use HDPE or LDPE sheets. they are nice and slippery on rocks and other debris.
good luck, and if you have any subaru specific questions, send me a PM. I am a rally tech, and have seen and worked on quite a few of these machines.
Oh and look up the 4EAT CDL mod. that one should suit your end use well.