The way the ram air works it that it forces air into your intake system, yes your MAF can only read so much air, but the faster the air an te more you cram in there the more it reads and the more fuel it dumps. The lower and further away you can draw air from your engine bay the cooler it will be and the better performance you can get out of the Ram Air. Throttle response wil increase, and I dont know about gas mileage. So in fact both myths are true, your getting more and cooler air then before. With the little particals of dirt and water on the road, there not a great concern, but there is a little catch plate the will force out little things with the force of the air. The kit sits back inside the bumper so there isnt really an issue with picking anything up, at least I havent picked anything up driving t and from Ny to Texas a couple times.