02 impreza RS

My advice is get a good repair manual, so you'll have all the torque specs. If you need specialized tools, check with local parts stores, some have loaner programs or low cost rentals. Craigslist is another good tool source, people buy a tool one time (like a cherry picker) then sell it as it's cheaper to do that then rent one. If you haven't already, join one or more Subaru forums and look for member guides on motor rebuilds. When it comes to removing head, intake, or exhaust bolts, SOAK them for days in PB Blaster or liquid wrench, use heat to back them out, never put a big 'ol breaker bar on them, too risky you'll just snap em off. I'm not that familiar with Subarus, but you can probably do the head gaskets with the engine in the vehicle, if you do pull the motor, then you may as well do the timing belt and water pump too at the same time. Pulling timing sprockets is no easy task, familiarize yourself with the procedure, you'll also likely need specialized tools like a gear puller or dial indicator. Good luck!

Thanks KenF. I believe from further research this motors sprockets and pulleys are all "keyed " so you can't mix them up and timing marks are easy to see.

Use top quality multi layer gaskets, check the heads for warp and prepare the mating surfaces really well. You could install new head bolts while you are at it and you should go ahead and install a new timing belt and idler wheels. You can do the job with the engine in the car but you will have a much easier time if you take it out.