Ok if you think the Kand N air filter is good your wrong. I have pictures I am willing to share to you all of what a K & N looks like after one day at the sand dunes in Michigan. I will admit I am still looking for a better filter. Everyone says it is about opinion, or they say just look at the test reports. Well for best filtration you are best to use the old paper filter by test results they filter the best. But they also starve the engine of much needed more air. Everyone that is using the donaldson type filter or MAC filter system is using by what I have heard not just on here but from people that have these filter systems the best filter system available as of now for the power strokes. The black dots on the filter is not dirt they are holes the size of dimes.