with that many miles the gaskets should have been done.
The fuel filter could be plugged, when you turn the key listen for the pump, it should prime. They like all subarus have rust / rot spots, could have been repaired always bring a magnent to test.
Headers and intake are what they are, but lowering springs I'd be worried depending on brand.
I would agree 3k is a fair starting price, but dont be suprised if he seems shocked.
Other than that remeber to bring a 10mm with you to inspect timing belt and when running give it a good listen while hoods open for any odd noises aka timing belt componants ect