The sway bar should be fine on any '04 STI, but the '05 and newer cars use a different style endlink.
I have the same bar on my WRX and after 3 years it was looking a bit on the worn-out side, so I took it off the car hit it w/ some heavy grit sandpaper to clean it, then some light grit sandpaper to prep it, and then put like 8 coats of krylon on it and it's as good as new now... and it even looks like a Cusco bar now since all I had on hand was dark blue paint.
A $100 and 20 minutes of work over the course of an afternoon and someone can have a bar that's as good as new.
Also, those old-style endlinks should be fine if you're not autocrossing, and even then, they're probably good enough if you're running the bar on a softer setup.