Well the problem is everyone tells me something different so I never get the same definate response to the questions I have.
I called Injen and asked their tech straight out and he said
"Stock your car is running rich to begin with. The intake will lean out the mixture a bit but not that much to cause damage. The gains from our intake is from the air velocity increase not by leaning".
I placed to call to Subaru service department at my dealership and this is what they had to say:
"Well, the CAI may void your warranty if you have an issue that can be pinpointed to that specific mod." -Tech
I said "Well, will it damage the engine at all?"
He replied "It may lean out the mixture abit. I've had a few people come and remove their CAIs and put their stock box back in because of CELS".
I've had the CAI on my car for like 2-3 months now and never got a cel. The piping diameter on this thing is identical to the stock one.
As far as the whole "The K&N oil can get in your MAF and blah blah. I have had K&N drop ins on ALL my cars and never once had a problem with it.