one thing you forgot on your poll
they flow more air, flow more dirt and will cause the MAF to gum up
THere was a flow test that compared all types of filters and flow rates... the K&N flowed MARGINALLY better than the stock paper filters, but flowed LESS when debris was present...
Not to mention that MANY have had their MAF sensor go bad due to the oil that is needed for the K&N filter... 400.00 for the MAF alone!
For the 60.00 that the K&N costs, I would have to go through 4+ paper filters to get the cost of the filter back... so not really SAVING that much in the long run
If you change 15-30k miles... 45-90 k miles to recoup the cost of one K&N ...they recommend cleaning after 50k... so you will need another 20.00 for the oil and cleaner...
Not to mention... have you looked at the K&N after 50k... yuck... clean closer to 25-30
"well the Racing guys use it" ... well they also re-build the motor after 1-3 races as well, so particulate matter is not a factor fr longevity to them
As you can probably see, I do not care for the K&N product