Timing belt service should be done on any suby around 100K. The thing about 22t's is that they are a non-interference motor so if the timing belt does break you coast to a stop on the side of the road. Replace the timing belt and drive away.
Do that on later model and you bend all your valves which turns into a MUCH more expensive fix in addition to the timing belt service. So when someone says it HAS to be done, they are right about later model but well its less of a risk on the legacy you are considering. $1500 is a good price for that car... and that is speaking from a good bit of experience with these.
Look for cracked nipples on the airbox, notorious brittle things after some years. Oil on or around the turbo, all the plastic lines feeding back into the turbo intake pipe also. Those parts are not too expensive at the dealer but start removing one and you'll break something else near it. All the heat cycles over the years make all that crap brittle and break. The power seat belts often fail evenutally and sunroof leaks, check the headliner for signs of water.