Is the 2.5 in a 98 Forester the same as the 2.5 in a 98 outback? I have never worked on a Forester and I am looking to put a 98 2.2 in one. I have done it to an outback but not a Forester.

98 yes. 98 Forester has the same DOHC engine as the outback. A 95-98 2.2 is a direct swap. 96-98 2.2 has single exhaust port heads, and needs the single port exhaust y-pipe to match. A 90-94 2.2 can be used if paired with an intake manifold from a 95-98.

If it has EGR you at least need the manifold from a 2.2 with EGR to keep the CEL off.