Well, the truth is, i don't even really use a case. So fan filters are kinda pointless. When i did use a case however, they just seemed to tedious to have to pull them out every month and clean them off. I would much rather blow out my system every 6 months.
The pantyhose will not cause static eleltricity because they are not rubbing against anything, and even if they do, they are grounded to the case so it wont cause any damage.
This is what i use for a case: