Oil seals are a chronic problem. Have had these replaced twice, once at ~50K miles, again at around ~100K miles. Did preventive timing belt at same time.
Had valve cover gasket replaced at ~100k miles.
Otherwise just normal stuff. Got car new and kept regularly maintained, am not hard on a car (e.g., has original clutch at 125K miles with no problems there yet.)
After having radiator flushed winter 2007, and thermostat replaced, surprisingly it began to run hotter than previously, but not actually overheating.
Summer 2007 check engine light came on, knock sensor problem. But no knocking heard. Ran it on premium gas for about 3 weeks until had time to have car in shop, then sensor replaced. Check engine light off after replacement.
Dec 17 2007, heard what sounded like very loud valve noise until well warmed a couple of days in a row. Stopped doing it when took to mechanic, so unable to diagnose. Had oil changed anyway. Ran OK until last week when suddenly knocking became overwhelmingly loud. No check-engine light! Took next day to mechanic, this time it was still banging, only worse. He said sounds like oil starvation happened, sounds very bad, serious engine damage, needs new engine, at least $5K. Despite the $ he stands to make on the repair, and fact the car is otherwise in very good condition, he says don't put any more $ into it. still trying to figure out what to do. Very disappointed in this engine, was waiting until more advance on alternative fuels prior to making another purchase.
AS far a going ahead with another... Apparently Subaru has done work to correct engine problems, so that issue might be gone in newer years. The car & options packages are best for price, but Subaru has not improved fuel economy, which is a major downside in deciding if I will get another at this high-fuel-cost point in time.