ihave not taken mine apart yet, but i have looked at the installation pictures for an intake.

from the little i know: the tube you refer to is going behind the turn signal....not to cold air, but to your stock resonator, which in turn pulls its air from the engine compartment.( the resonator not only restricts airflow but dampens the noise the motor makes...which most hot-rodders would rather hear than not hear.)

anyways... the resonator has to be removed to install the icebox because that is where the new intakes mouth is positioned.

you can look in the DIY section and see where someone made their own icebox by removing the resonator and rigging a hose to the bottom of the stock airbox, it would work but you loose the smooth and efficient interior of the icebox....unless you are really good with fiberglass or some other molding technique......

PS... there is nothing special about a short ram intake compared to your stock one, at leat not as much that you couldnt somehow rig your stock intake elbow to a filter after removing the stock airbox and get the same gains.....the only difference i am aware of is the material they are made of (metal aftermarket vs rubber stock) im guessing this isnt done more often because.... well i dont know why...anyone have an answer?