I use K&Ns on all my vehicles because they can be cleaned and used again. Have not had any issues with any of them.
I have the BMC Street filter which is very similar to the K&N. I actually swapped back and forth between the BMC and stock a couple times for some back-to-back runs and couldn't tell any difference with my butt dyno. I do like knowing I can wash and reuse it but I wouldn't buy it expecting a performance gain. I don't know about going 50k between cleanings. It seems like a lot of members have reported some pretty gunked up filters after just 15k if I remember right.
I think 25k or one year is the recommendation from K&N. I check mine every 15k or so. Depends on the riding conditions as to when it gets clogged up enough to clean. Just looked at the one in my Prius and it needs doing so I'll do the bike and the Prius this weekend.
There are several filter studies linked on some of the other air filter threads. K&N consistently did poorly as a filter.
There are several filter studies linked on some of the other air filter threads. K&N consistently did poorly as a filter. That increase in breathabilty is because of an increase in pore size. K&N's come into their own in high dirt environments. They do not plug and are easy to clean. As a street filter they let a lot of fine stuff through. The stuff may be too fine to affect performance and wear except in the very long run. After reading some of the studies I am sticking with paper. The performance increase with K&N is insignificant for our application.
Got a link to any of them?
I still think they are inferior to a good OEM filter.
Yeah, right. I laugh in your general direction...