1st K&N puts out one of the best filters oth there on the market
Actually thats what K&N's marketing wants you to think. Actually their filters are actually sub-standard compared to other alternative solutions.
K&N Filters...
1) Filter less then stock paper filters.
2) Sometimes result in a performance loss
3) Are generally constructed of poor quality materials.
Holding a K&N filter in your hand (especially a cone based), you can feel how flimsy the filter is. Press on the pleats and they bend. Press on the ends and they bend. Their constructed as cheaply as possible, then have the price jacked up to make maximum profit.
Technically the best filtering media is paper, hands down, and proven in multiple tests. Cotton/oil based filters usually come in 2nd or 3rd, sometimes behind foam.
K&N likes you to believe that the filter is in some way a "restriction" and tries to prove this through varied marketing skeet all over the place.
Realistically the filter is usually the LEAST restrictive part of an intake assembly.
For example on the Mazda 6, if you flow bench the airbox with and without the filter, there is only a 6% difference in airflow.
Leave the filter in, but remove the resonator, and the airflow increases 12-15% (with filter in).
Do the tray mod, the flapper mod, and the resonator mod, and leave the filter in, and you increase airflow almost 40%.
Some options for paper cone filters are...
http://www.baldwinfilter.com/
If your looking for a cotton based oil filter thats far superior (in every way) to a K&N based, check out S&B.
http://www.sbfilters.com/home.htm
Their filters use deeper peats (better filtering surface area), larger pleats (better surface area), tighter meshes (better stability/strength), reinforced end caps (better stability/strength), and have a unique open cone for increased noise/sound, and technically airflow, but as mentioned earlier, filters aren't a restriction.
For more information on this topic, and links to tests and explanations about the true facts about K&N type filters, visit...
http://forum.mazda6tech.com/viewtopic.php?t=160&start=0
and
http://www.bobistheoilguy.com
Knowledge is power, never listen to marketing!
Here's the difference between the crappy injen K&N filter, vs the S&B replacement on my Injen CAI.
Which one would you rather have filtering your air? (Note K&N filter damage)