ive got a hks pod, and ive had the car for about 22k now (over about 5 months...)
Daily driver on the F3, so the car (and intake) sure get a workout..
I replace the filter element every 10k (Autobarn, $65 - usually order in) and yes they are pre-oiled.
I have also regularly checked the intake pipe and AFM, and i cant say that there is an exsessive amount of dirt, crap, etc getting through..
Like anything, regular maintanence is a good preventative measure if you are worried.
All pods are going to allow more airflow (and hence more particles) than the stocker paper filter (more flow = less restriction) - so if you are super worried go back to stock..