I took the panel off on my 07 to put in my own filter. There is a screen in there but it doesnt do much. I poked it out and then used home filter screens for a home. They sell these filters for home floor registers and they will fit.
I bought a whole package and put almost all of em in mine. Then when i went to use my fan it didnt hardly blow any air. The cabin fan is very small and weak so if you put on in you better check it because it will rob the fan output.
You will need to decide how much filter you want to sacrafice how well the fan works.