I'll just let the video below speak for it's self.
Take note, this is more of a example of what the intake sounds like from a distance than a DIY on a MK3 VW Jetta Vr6.. so make sure you have your sound/speakers enabled. You can find full instruction on how to do a ported intake or swiss cheese stock air intake box at VWVortex.com
Here is what the intake sounds like from the inside of the car.