I believe it's because Volant's dry filter technology is not up to par. I'm not sure if the prices are the same for the oiled filter kit vs. powercore kit, but I think the verdict (according to Drew) is to run the Volant intake with an AEM filter if you want to go with a dry flow. I'm sure he'll chime in if I'm off on that.reason?
I have no doubt that if properly maintained they'll be just fine. I was just stating a possible reason to go with a dry flow over an oiled filter. On my previous truck there was an issue with the oiled filters screwing with the MAF sensor but I think that was more due to the tonsil design of the sensor than the filter.I've run oiled (K&N) filters since the late 80s and have yet to ever foul a MAF sensor.
If you apply the oil properly and only on the side required you'll have no issues.