well if he said 18ft ..that is very good air.. I would not call it mineshaft air but very good. And if you run in 2000-3000 ft da..That is alot of change depending on how your car was jet'ed to start with. It could be very lean and to add to that a headwind would make it leaner on top of that. one anytime you add load to a car it lean it and head wind pushing more air in the scoops.