I am returning my 2004 STi back to stock. Up for sale is air filter by UniFilter (http://www.uniflow.com.au/) that will fit your stock 02+ WRX and STi stock air box. I will also include mineral turps for cleaning and the "oil fix" for re-oiling. So, you are getting the whole package not just the filter alone.

Asking for $15 to take them all. The filter in great condition. It may need to clean up and re-oil before you use it.

Thanks for looking.

Pictures below:

http://sfbay.craigslist.org/sby/pts/300457119.html