you dont need to change the oil at a shop. there are a lot of diy'ers around here, myself included, that do their own oil changes. plus, now that you MUST use synthetic, diy oil change is significantly less than the $90+ you will get charged at a dealership.
best advice i can give? get to know your car, the sounds it makes, the way it feels. your ears are very important, and subarus like to make a lot of sounds. and dont drive in a manner that puts a ton of stress on your car all at once. they can take some abuse, but in reality, they are just passenger cars, not racecars. drive spiritedly, but not like an idiot, and your car will reward you with thousands of hassle free miles.