The box is designed to improve the volumetric efficiency of the intake and help with sound attenuation. The size and position is intended to provide optimum resonance of the pressure waves created by the stroke of the pistons. Pressure waves (air vibrations at the 'speed of sound') are generated and channeled out the intake - outbound pressure. The box absorbs much of the force of the wave creating a partial vacuum at the neck of the box, cycling an inbound pressure wave through the intake. Because of the fixed length from the valves to the box and the fixed size of the box, it has to be engineered to provide peak performance at a particular rpm. Above and below that point it will provide less efficiency.
You don't need it, but Porsche didn't put it there just because they like to add on extra plastic thingies. It helps the engine run better.
That's my understanding, but my degree is in Geography, so I could be confused about this sort of wavy-engineering-and-physics stuff.
Try this:
https://itstillruns.com/air-intake-resonator-do-12156112.html
