I think that common sense must override. As I stated before, an air filter is designed to filter/clean the air. K&N fails miserably. I know for a fact that many participants of two Toyota 4Runner boards have have pretty much pulled all K&N products from their vehicles. This included FIPK units and strait filters.

The information listed below paired with visual inspection of the actual filter convinced me of the failing of K&N to adequately protect my vehicles from damage. I would challenge those who use K&N to actally conduct an experiment using the K&N vs OEM filters by doing oil analysis (usually about $10/test).

I won't begin to discuss the problems with the FIPK units and the ability to suck hot engine bay air. This without argument degrades turbo performance immediately.

Time is the best teacher. I can merely state that I have used an Amsoil Air Filter unit. I use Amsoil oil and oil filters. I have had an oil analysis done after running 17K miles on the same oil. The bottom line showed minimal contamination by particulate matter and recommended to change the oil filter and continue using. I chickened out and changed the oil and the oil filter.

You're right - don't believe manufacture/commercial advertisements (in total). Do yourself a favor and weigh them against personal experience and common sense.

Andrew T. Watson