Wait a minute the activated charcoal filter sits down in the plenum, and cant be removed unles the wiper mechanisim and the valley pan is removed. You will have this filter if you have a filter switch on the dash. The other filter sits on top of the blower and can be activated charcoal, some after market filtrs are just pain pleated filters, MB recently reduced the price of those, I dont think you will get any granules into the system, they just do a better job of filtering.