This is a discussion on Scratched my WRX Front Bumper!! within the Exterior & Appearance forums, part of the Tech & Modifying & General Repairs category; I scratched up my front bumper real bad!! I took a U-turn like a noob.. fk now it all scratched.. ...
Lol, All I have to say is, "touch up paint." There's not much more explanation than that. Smooth it (sandpaper), prep it (soapy wash, then mineral spirits, dry), spray it (with can in hand pointed in the right direction), polish/wax/whatever. Done. Just like that link you posted.
Otherwise take it to a body shop or something.
Like he said. Or live with it...there will be more to come.
I have a few (front and rear bumper) from other people who were considerate enough to help me buff my paint with their cars and didn't even leave me a note so I could thank them. Such is life.
Mask off, Wet Sand, Spray w/ matched rattle can paint, Clear, Buff... or pay a shop to do it
-Your going to have to take it to a body shop. They will have to repair it and it will require a 3-stage paint job. Make sure they color match it as best as possible. SWP is the toughest paint job to get back to OEM specification. In fact you will never have OEM paint again once that is fixed. Your front bumper will need a complete full paint job although your scratch isnt the largest I've seen.
-There is an alternate solution which would be to go to Subaru dealer and ask for touch up paint for the SWP color if you feel like DIY.
If you want it done right...do the first option. Good Luck mate.
FYI, the touch up paint from the Subaru dealership is $12 for a bottle the size of nail polish. The brush is similar to a nail polish brush as well. It might be worth a shot for the money.