Darekc I've used the K&N for years and had no trouble with them.
Had Roadhouse slip-ons with the K&N and found no reason to rejet.
you may have to tweak the pms
I would put a K&N or amsoil has a new filter the dosen't require oil, in the air box and not drill the holes.
At some future time you may want to return to all stock for a reason and
have to find another airbox
I have since put my stock exhaust back on with stage one drilling
and it still runs good. Just my .0003 cents worth.