I've not heard much on the K&N specifically but my buddy with a 3.7 wrangler did the full cat back exhaust and CAintake and then did the superchips 87 tune and said he could tell quite a difference after the tune but not so much before. He contacted the superchips people when he was debating whether or not to buy it and the rep asked if he had already done exhaust and intake. At that time he hadn't so he informed the guy that he didn't have either. The rep said don't buy the flashpaq (at least not for the power gain) cause it wouldn't help unless he upgraded the breathability of his JK first. He eventually did and then bought the flashpaq and is now quite satisfied. He was a little down on power as he's running 35s with 513 gears and a 6 inch lift. (It's the guy in my hidden falls pics with the white rubicon). Lucky him though cause he was able to change his shift points to help compensate for the gears and wheels. I don't think we can do that with the flashpaqs for the commander.