Just want to make a clearification. A K&N does NOT filter better. It allows for a higher flow rate at a given Delta P. (pressure change accross the filter)
That reduction in restriction allows for more air flow.. and therefor more TQ *potential*.
Now.. I've personally rebuilt engines that have used K&N filters. And while I do see traces of debris in the intake manifold. I've yet to see valve seat, valve guide, or cylinder ring/wall wear because of the increased debris.
My solution is to run a conical K&N w/a outerwears pre-filter. You get the best of both worlds that way.
He who is enslaved to the compass is free to sail the seas