Yes you need the bumper, headlights, fenders, And hood. Unless if you want to keep the stock hood, can also remove the stock scoop for a more aggressive look n replace it with a 2002 or 2003 sti scoop
That only apply to 04-06 model. If you start with 06-08 only sport bumper cover is needed.
Also 07-08 sport XT AT is the only one that came with stability control.