Replace or rebuild? 2003 Subaru Outback

This is your choice. If you plan on keeping it at least another 50,000 miles it might be worth it but of course you may be replacing the transmission and other major components. The head gaskets should be multi layer, not the pistons.

Seventeen years and 213,000 miles is a good run for any vehicle. If the engine were to have a major problem such as the head gasket, for example, I'd replace the vehicle. It would cost more to fix it than the vehicle is worth. Plus you'll still have everything else to worry about. The transmission, electronics, etc. can and will give you problems! Plus, replacing an engine is a major job that involves unplugging and moving wiring harnesses, air conditioning components, etc. that have most likely never been touched since the vehicle was built! Bad connections and accessories that don't work or don't work right after the repair can be common. Along with ongoing check engine light problems because of the wiring being moved around and reconnected. It's better to move on rather than spend the money to try to hold on to the vehicle you have. Everything has a lifespan and when it's over, it's over. Hope that helps! Jim