errm yes they do, dirt penitrating something.iv still got it.Why use one that dont stop dust? my pond filter is finer foam than pipercross and cant keep the pond clear .Why do hoovers use paper filters, to stop dust coming out the back of it .If it was a pipercross filter without oil ,it wouldnt stop dust. 
Wrong on all counts, I will take a picture of the box sometime it says special non oiled for vag group cars to avoid issues with the maf, I think the older ones did need oiling but they are now a dry foam type design.
k&n or green air filters are the best at stopping the finest dust.pipercross are better but let it all through (dust) . 
Wrong again, many people are using them all ok as posted many times they are the best choice to avoid problems.
iv changed my mind get green ,cheap but better. 
Why cheap, if it ends up causing maf issues you are not really saving any money in the long run.
i`m 50/50 on this one, as i`m sure the pipercross are supposed to be oiled but us mk4 owners choose not to for the mentioned reasons.
Nope they are a non oiled filter.