Subaru will wash their hands of it, they stated in 2010 that it was the owners fault for tuning, driving them to hard, not servicing them properly etc etc total bollox but saved em millions in remedial work.
2.5 out the box is !Removed!, very common for pistons break the ring lands , head gaskets to fail etc. If it's gone to API they should be well aware of the issues and put none subaru pistons, gasket and head studs in then no more issues down the line with it :)