years ago it was relatively easy to change a head gasket, what makes it harder now is all the "stuff" you have to remove to get to the point that you can get the head off. maunals are available, "chiltons" usually has info on svx as well as other subarus. if you're intent on going it alone, keep in mind the head should be closely inspected with a micrometer (doesn't hurt to inspect the block as well) to make certain neither has been warped. also, you'll need a torque wrench in replacing the head. it can be done, years ago with my first car (a rambler to show you how ancient it and i are) a freind who knew how helped me do one. i don't know if i would attempt it today though.