hmmm. ihave the regular k&N drop in filter it's great but i clean it with the special cleaning kit for it it's like 9 bux and it come with that special red oil. i clean mine every 4 months snice is so dusty out here where i drive. BUT ONE ADVICE FROM ME> Please pay 9 bux and get the kit cuz if you just wash it and dry it without putting that oil on it it will screw up the filter pluse it won't filter good and will sound like shit basicaly.