Standard Paper Filter - It may be time to replace your Pollen filter, especially if you have allergies. This is the filter which brings clean air into the cabin of the car, and it should be replaced on a regular basis. Porsche recommends changing the pollen filter every year, or every 12,000 miles.
Porsche recommends the charcoal version of this filter, but this is a good filter at a reasonable price. Made by Porsche.
This is known to be an easy installation, the pollen filter is located under the front hood, under the black cowel panel.