Taz,
What I want to know is the black dust oily? I have not examimed a ton of these, but the few I have seem with the black dust seemed like the dust was fine and powdery. To me it did not seem like dirt trapped by an oil film. But then how does it stick to those blades while spinning a bazillion RPM's?
Bob is correct with the oil filter debate. There will be those with stock that say no problem, there will be those with K&N or other oiled media, that say no problem. There are those with oiled media that have had problems, and those ( like me ) that say its all because of over oiling and improper installation. There are those that are just nervious about adding oil to the intake path.
I am all fine with each choosing thier own, but I would like to know if there are other explanations, besides the filter debate.