[poorshe911]

I've been looking for some kind of study but couldn't find one.
I saw an article, I think on this forum, about people cutting holes in their filter covers and saw a difference on a dyno. Don't know if it was with a K&N or paper though.
Anyways, I wonder if anyone has used a K&N for a long period and has gone through the air system during a rebuild or etc and found any issues.

I've used the paper filter the last couple seasons and the car ran very well .. didn't detect much difference. Doing a rebuild and getting everything squeaky clean along with the cams change I thought I'd get the most I can out of the air intake system and actually now see a performance increase.

Milo,
That's interesting. I never would have thought that to be the case. Does it run better?