Hello Anna and welcome.
Don't touch the air intake unless you are going bigger turbo, the Subaru air box is very very good and plenty airflow for even more powerful turbos than your stock one.
All you need is a Turbo Back Exhaust system(
TBE), a 3port boost solenoid(Grimmspeed or Cobb etc) and a tune. It will be plenty fast and you'll be happy for a while.
Do not touch the wing unless you want to be called a John Dick and Harry, of course the wing serves its purpose for downforce.