What kind of lowering springs do you have? You might need struts soon.
Do you have aftermarket endlinks as well or just sway bars? If not, you might want to consider buying some front and rear endlinks.
Besides those, other good mods for you would be: K&N panel air filter, GP Moto intake silencer delete, short shift lever, and/or polyurethane bushings anywhere and everywhere.
Your next serious round of mods should include a catless up pipe, bellmouth downpipe, any cat back, and Stage 2 reflash of some sort.
07 WRX (Albins 5MT + Blouch 20G)
Jorge Carrillo Tuned (365 whp/340 wtq)