I have had two problems with the new 6.4 AFE stage II filter.
First problem, the intake tube supplied by AFE in the kit has a bad fit up to the existing factory tube to the turbo. AFE is aware of the problem and is working on a fix. Unfiltered air can pass due to this problem.

Second problem, check engine light came on after 2500 miles. Dealer claimed the air box was the problem due to too much air flow. Can't tell if this is true or not, but its what the dealer told me.

I don't know if any of the other aftermarket guys are having the samr problem.