Welcome!
2003 was the first year of a model change and kind of a transition year with respect to head gasket problems. While 2003 didn't exhibit the near-systemic problems of the previous SF model, incidence was a bit higher than that in the later years of the SG (-2008) model. That having been said, there are a lot of us here with high mileage 2003s that are absolutely solid. Like mine! Interestingly, I bought mine in December of 2002, very early in the model year, so it doesn't seem to be a matter of their using up old components before switching over to the new improved ones.
Since people tend to talk much more about how bad things are rather than how good they are, I set up a few polls regarding head gaskets, giving members the opportunity to vote Yes or No regarding problems that they might have experienced with their own Foresters so that we could get a balanced report. You can see the polls
here.
As for upcoming big items of scheduled maintenance, there are none. The only piece of scheduled maintenance in the life of a Forester that could be described as large is timing belt replacement, and that's not due till 105k miles. Everything up till then is just routine—plus of course replacing anything that wears out like tires. You can see the entire maintenance schedule at
cars101.
As for Good Dog's comment regarding an XS that's available in your area, do be aware that there are a couple of major differences between the X and XS that were the deciding factor that led me to buy an XS. (The XS
Premium part was for fun!) These are disc brakes all around vs. drums on the rear, and limited slip differential. Cars101 is also the place to go to get the complete list of features associated with each different model.
For more info about Subarus in general and about our forum here, check out the sticky threads in the
New Member Introductions Forum.