That is true, but it sucks it down anyway halfway with stock airbox and the new updated Filterelement.
I did a second opening to the airbox that is open most of the Time and can be closed manually, but in Iceland I had it closed all the time, it doesn't realy matter to the enginepower, maybe a little slower spool up of the turbo but fully 28psi Pressure in the same range as with the stock airbox.
So I got mixed feelings about the snorkel but I needed it for Iceland, there are no bridges crossing most rivers so you need to ford them.
The RAM did a great job anyway, like it still like first day.
The picture in calendar is from Iceland, sadly they don't mention it.