Well, I don't know about air restriction on the dust filters. I know on my truck that it runs better with no air restriction. But when I put the air filter on, it goes back to normal. But when I put the K&N filter in, it runs a little better than the stock filter. What I'm trying to say is this. Look for a filter that you can see through. Even if you feel like it's not doing a perfect job (which it won't), you can be happy because it IS keeping over 50% of the dust out.
Those sound dampening mats don't work. Not for this use anyway. They work when you attach your sub box to the back of your truck's cab. Then it takes the recoil from the subs and doesn't transfer the violent vibrations to the bone. The sound you're mostly hearing is the sound of air passing through narrow ways, fans spinning, ect. It's not the actual vibration the fan is putting out.
<b>I'm an unhyphenated American.</b>
Intel Q6600 @ 3200 1.4v
Abit IP35 Pro "The Snake"
2x2gb A-Data @ 800
Diamond HD 3870 512mb
Great FORD TRUCK