A bit back, someone here had asked about gutting the airbox. I don't have a clip of the sound, unfortunately. If you're familiar with a cone, the box is quieter inside the cabin. Most the sound escapes the front. You can also keep using cheapo stock filters.
Here's some pictures to kinda give an idea of how it looks.
Outside -
Front -
Pieces -
This is the silencer section cut out. I made sure to keep a lip around the edge to seal, even though I wasn't sure I had to. -
These were the cuts I couldn't reach with a Dremel. I finished with a drywall hole saw and didn't clean up the edges because ..why?
There it is if you've been thinking about doing the same. Not much to it, really. Enjoy.