subaru 2.5l H4 is an easy motor to work on. my 96GT legacy has the same one, im at 147k miles so far. my 95 legacy wagon has the 2.2L motor and i was able to replace the TB, water pump, all the idler/ tensioners as well as the front seals in a day in my driveway. i didnt even take it into the shop for tool access like i normally would.
never use stop leak in that engine.
keep an eye on the overflow reservoir for greyish gunk build up. this is the usual first indicator for HG issues, as these motors are more prone to pop on the inside, allowing the exhaust gases to get into the coolant, not usually coolant into the oil.
there are easy to do bolt on upgrades for that motor as well. fun cars with lots of options.
my dane/ lab mix fits in both my legacys, sedan as well as wagon along with all 3 of my teenage kids.