I'm not sure about disregarding the importance of an air filter with good filtration. If you perform a periodic oil analysis of your drained oil, you will start to see a correlation between contaminant particle counts AND sizes in the oil when comparing a less effective AIR filter to a more effective air filter. One analyzer reports that in their results, over 80% of the contaminants in engine oil are admitted through the air filter of an engine. All that dust and grit is being pumped around in your oil since it cannot be caught in a standard 20µ single-pass oil filtration system. Cheaper automotive oil filters are not even 20 micron, but are more like 50.