Wotcha and welcome - that is a clean look motor you have there, as Gambit said decent fuel will make it run lovely and when you service the air filter dont have one with oil, an oil free hi flow panel filter will keep the airflow sensor fine.
but I must warn you with Subarus modifying can be addictive its a slippery slope but one hell of a slide, have a browse of the forum as we are fortunate to have members with some choice machinery and lots of different modifications