I have the same model as you, just bought and fitted a front lip in flat black, makes the car look 100% better. Easy to put on too, took me all of 15 minutes. As for the vortex generator, I personally think they look better on an evo than on a wrx. But that's my opinion.

As for the scoop, I reckon a repaint would be best. That whole black panels/wrapping thing is both good and bad. I was thinking black scoop as mine is a silver peanut, combined with a black lip and such it may work, but with World rally blue, I'm not so sure.

For now, I'd look at a respray/trying to source another one from a same colour STI.