The Porche Club performed testing and found no performance increase on K&N filters. I have run them in almost every vehicle I owned since 1973 (dirt bike). When new, they allow larger particles tha the paper filter then get smaller as they collect dirt. The dirt soaks up the oil and becomes part of the filter. This is at the micron level. I like the K&N's but they mostly just make the intake a little louder. I doubt it could hurt the air flow sensor. It is a hot wire thype, isn't it? How could it possibly hurt it by allowing particles 2 microns larger than the paper ones? Urban legend?

I like the fact that you cna clean them and they last forever.

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Steve
1985 Mercedes 500SL Euro (Gray market)
1995 BMW 520i Euro (Gray market)
1992 BMW 525it Wagon
1994 Honda Del Sol Si