I did a Tighed1/ Code3 (sounds like a score) variation. I was worried about the air cleaning efficacy of that little green Code3 foam filter. After seeing the Tighed1's DIY job I added a single sheet of hepa filter on the outside of the foam. I lost a little of the scream but it's worth it to know I'm not sucking huge amounts of earth into my pricey AMG engine. Now I only suck in a little lol.