Long time debate - will never be answered to all satisfaction Some say including dealers that the oil from the filter will dislodge and clog/fowl sensors, K&N obviously states that is not the case and is safe. I use them and I am in the middle, sure if you put way too much oil on it obviously not good. Another concern complaint is if it allows more air flow than it must allow more particles into intake. Again I don't think they are valid concerns but this is just my experience. You'll get differing opinions from the experts as well. Honestly I haven't noticed power change with the LR4, but I haven't done dyno or any other objective data monitoring.