I moved your post... thread to the "Motor Conversions" sub-forum, which looks to be a better fit. :wink:
What you want to do is not "plug & play", requiring the entire '04 XT engine + wiring harness. Once the '04 XT engine & wiring harness is installed, you'll have to merge it with the '03 XS wiring harness. If you don't have the skills required to do this, you'll have to find a specialty shop that can do that for you. :icon_eek:
Most members would tell you moving on to an XT is the lower cost option. :frown:
We’re the best Subaru Forester Owners Forum to talk about the best years of the Subaru Forester, modifications and reliability history of the Subaru Forester.