K&N filters: I really cant speak about the K&N motorcycle air filters but, yes, their car/truck air filters do let in a lot more dirt. They do keep out rocks & small birds. I suspect the bike filters would be about the same. I wont use them. On the other hand the K&N oil filters are excellent. Done a fair amount of research on <STRIKE>them</STRIKE> oil filters & use them on several bikes. Don't know if they make oil filters for the XT225 though.