I saw, and replied to a similar thread on AZ. BTW, my first post here 
Regrading this statement from SSP_255, 3.0L self study guide:
The intake noise is damped by a Helmholtz resonator.
The intake resonator is not a silencer and is not designed to make the car more appealing to soccer moms. Noise means more than just an audible signal. In electronics, noise is unwanted random addition to a signal. In the intake system, noise is unwanted addition to laminar flow. Sound waves travel through ___ (fill in the blank). If you said “air”, you are correct. When the intake valves close, the air bounces off of of the valves (see explanation below) and creates a “ping”. That ping is noise, unwanted addition to laminar flow. The helmholtz resonator reflects the ping and actually boosts the input of air into the next cylinder in the firing order by increasing the velocity as the intake valve opens. This is due to the frequency at which it operates. The ping from the previous intake valve close is timed to pong the next intake valve opening in order to ensure that there is no dead air space in the manifold. Sound reduction is a side effect.
My response on AZ:
First off, I applaud “out of the box thinking.” Innovation comes from challenging the Status Quo.
Now, here is why I would not change my air intake in this manner however:
The air intake system on our Audi’s has been designed to deliver the most efficient method of getting air into the cylinder. It is designed and tested using some of the most advanced tools available. These tools have been developed specifically for measuring the effects of airflow from the leading edge of the air intake all of the way to the lip of the intake valve(s).
The most efficient delivery of air is laminar. Laminar flow essentially means that the air moves directly through the system with the least amount of turbulence. We want the outside cold air to move through the system and into the combustion chamber as quickly as possible so we can take advantage of the cooler oxygen rich environment that this air provides. Turbulence in the air intake reduces air flow as it creates opposing forces that fight against the direct flow of air. This turbulent air can gain heat as it continually comes in contact with the warm walls of the intake. Turbulence also causes fluctuations in the mass of the air.
Why is air mass fluctuation bad? The air mass is measured by the MAF and is used by the ECU to balance and deliver the correct air/fuel ratio to the engine. These are closed loop systems and the O2 sensor checks to see if the ECU made the right air/fuel mix decision. If the system is stable, that is the air mass doesn’t fluctuate, the measurement, adjustment and testing would plot to a smooth curve. The air mass measured is the same as it gets to the combustion chamber and the air/fuel mixture is correct. If the air mass is constantly fluctuating, then the system is constantly making corrections and a plot would look like a series of wild peaks and valleys as it constantly tries to measure and correct itself. The fluctuations cause the wrong air/fuel mixture to be delivered to the combustion chamber.
There are two things that can have an adverse effect on the air intake and create air mass fluctuation. These are Air buffeting and Resonance.
Air buffeting is something that I think most of us are familiar with. Roll down your window or open the sun roof at certain speeds and the cyclic pressure of the air passing over the opening creates an air hammer effect. How do we solve that problem? Well, we could say f’ it and close the window or sun roof, or we partially open another window, right? The pressure equalizes and our ears eventually stop bleeding. The same thing happens with the opening of the air intake. Air passing over the entrance to the air inlet creates a cyclic pressure differential and the air mass constantly fluctuates. How is this problem solved? The same way that we solve it in the passenger area, we create another opening that helps to equalize the pressure. Just before the air filter, another opening allows air to slowly bleed off through the fender well. This allows the pressure inside the intake tube to equalize and stop the buffeting. In turn this helps to create a laminar flow along the airs path to the intake manifold. As air passes the MAF the air mass is stable and information sent to the ECU can then set the correct air/fuel mixture to hit the cylinder at the right time due to the laminar flow of air. I think blocking off the equalizer opening into the wheel well makes the MAF’s ears bleed.
Resonance. Resonance is caused by the pulsing draw of air into the engine. The engine doesn’t draw air steadily like a vacuum cleaner. Each cylinder only draws air 1/4th of the time and this is during the intake stroke. While the cylinder is drawing the air it also isn’t at a steady rate. At top dead center (TDC), the piston stops, changes direction, the intake valves open and the air is drawn in. As the piston reaches for bottom dead center (BDC) it moves faster through the stroke so the intake is progressive. At BDC the intake valve(s) close. Suddenly, all of the air that was rushing past those valves is stopped and the air around those valves bounces back in the opposite direction. Remember, for every action there is an equal and opposite reaction. That pressure wave can travel all of the way back through the air intake system and cause turbulence. How can we absorb that shock wave so we don’t interrupt the flow of air for the next cylinder? By installing a resonator just before the throttle body. A helmholtz resonator to be exact. The pressure wave moving in the opposite direction of flow tries to ram air into the neck of the resonator. The pressure inside the cavity increases and the air bounces out equalizing the pressure and keeps the wave from disrupting the laminar flow. In ricer terms, removing the intake resonator makes their cars “growl” and the sound is always more important than horsepower or fuel economy.
Your results may vary. Opposing view points welcome. Additional pepperoni available upon request.
Where I mention “we create another opening that helps to equalize the pressure” , I meant that the engineers have already created the opening to the wheel well just before the filter box. it exists on the stock A4 B6 3.0L setup already.
In the last paragraph I mentioned “By installing a resonator just before the throttle body.”, and again, that exists on the stock A4 B6 3.0L setup already.
To summarize, the best setup for performance , IMHO, is to leave the stock air intake system alone for a NA A4 B6 3.0L. Once we all get a Supercharger to bolt on in the future then we may need to rethink it