I have used K&N Filters on most my cars and never really lost any power, i make the effort to shiled it and get cold air to it, but if you make the effort, the added noise offsets the possible loss of power (which i never experiance) but i never gain any power thats for sure. nor did i when i drilled my old box... so personally i think its down to lots of noise, and no power gain, or less noise ... and no power gain. induction kit looks better though!
