Let's make it 3...
A. I had the K&N for awhile, never drilled it. Due to an extremely dusty work environment, I went back to the stock filter.
B. Even though the K&N is supposed to flow more air, it can only flow what you give it, up to the limit that the engine can take in. ( airbox restiction and pipes - inflow/outgo).
Drilling it would allow more air in.
The crux of the biscuit is how did it run before, how does it run now, and what do your plugs indicate?
