pleated paper is fine but I think you will find the guys who run Baja and other dusty stuff use the double foam. the stockers in my quads are great. I have to laugh when I see guys cutting up air boxes to make room for "more air" rather then leaving well enough alone. by the way use a good set of cleaner & oiling products. I see to many that just spray shit like pam cooking spray when good stuff is avalable everywhere.