2005 forester x engine into 2004 forester xs

I am pretty sure the 2005 has variable valve timing and the 2004 does not. I would look for EJ251 engines prior to 2005.

Should swap right over. The 2005 was the final year in the U.S. market that didn't use variable timing on the 2.5L motor for the Forester. I know because I'm having a hard time finding a replacement for mine on my 2005 XS Forester L.L. Bean. Good luck!