It allows more air to flow into the engine. The sounds can be compared to an induction kit but I's say personally it's better. Not only that but it has many other advantages.
One is that it is cheaper, which is always nice,
Also it's a better mod than an induction kit as it utilises the standard airbox and help shield the intake air from heat from the engine, which an induction kit does not.
Yep 100% definate, you will get exactly the same noise from this as you would a K&n, if not a better noise. I did make a sound recording on my camera but the noise was that loud my camera microphone couldn't pick it up properly.