i redline my engine when it's cold, which everyone tells me is bad, but i figure it warms it up quicker lol i haven't noticed anything go wrong in the past 4 months with me doing that... i think the only time you really feel a difference in power is when you go from a stock filter that's full of grime to a brand new, clean k&n filter... the reason you feel the power is because it wasn't able to come through before... but it's cool lol