Subaru parts: headgaskets, PCV valve, radiator hoses, radiator cap. Timing kit - pulleys, tensioner and belt. AISIN is a suitable supplier of OEM Subaru timing components.
Absolutely resurface the heads.Don’t check for flatness it’s an archaic waste of time.
2 valve cover gaskets, 6(?) valve cover bolt grommets, 2 cam seals, (1 or 2) cam cap orings, oil pan gasket, crank seal, oil pump oring. 2 Exhaust manifold gaskets, 2 intake manifold gaskets, rear main seal. I’d get all subaru usually but many of these have good aftermarket alternatives.
Tighten the oil pump backing plate screws. One or three are always loose. Use a quality driver.
Reseal the rear separator plate - a 93 shouldnt be plastic but replace with metal if it is
Install a new knock sensor. By far the single most common sensor to fail. New radiator and Subaru hoses and cap.
Crank pulley - install a newer hood condition used one or buy new.
Ive never seen Subaru valve issues in EJs so I usually leave valves and stem seals untouched.
Splitting engines isn’t my speciality (if anything even is haha) so take this lightly but I wouldn’t recommend splitting the block.