full disclosure, Cobb has offered to buy back my downpipes and intake. They are lighting my ap for the trans tune gratis. In exchange for the trans tuning, I've agreed to test it and provide feedback.
yes, I would not recommend the cobb intake in a really dusty environment or for desert runs. It is oiled. even though you can get a prefilter, the filter cakes very quickly and can foul an intake sensor if left uncleaned.
it works great for a mostly street driven truck and actually provides snappier throttle response than some others, but for the dirt, you need a dry filter.
I am a fan of the intakes that offer a donaldson filter option. (blue circular filter). I have to remove and shake the filter out every 500 dirt miles or so. ( which is a head and shoulders above anything else that I've tried, including the factory filter options)