I'm all about immersion and losing myself in a scary and unforgiving apocalyptic world, similar to Metro 2033 or the stalker series.
However, I already have a handful of mods ( Directional pip-boy light, Realistic lighting ) and a few others that keep me on my toes.

But I can't seem to find a gas mask / muffled sound mod!

What I mean by this is whenever you are using a helmet that covers your head, you get an effect that feels almost claustrophobic.
It immerses you into the game, makes you feel like you're actually there. It's hard to describe but it essentially covers your hud in
half blackness and leaves a hole/holes where you can see. Similar to the binoculars or scope.
Here is a screenshot to explain, however it isn't very good and you can only see the cracking of the mask on the screen.
http://www.smartones.me.uk/wp-content/uploads/2010/03/metro2033-20100320-1804262-1024x640.jpg

Aswell as not being able to find this mod, I've also been looking for one that muffles sound when you are wearing a
full size helmet, as if you have water/padding in your ears.

If anyone knows of ANY mods like these, please give me a hand! I've found one called "HUD effects" however I wanted to know if their was more.
Thanks for any replies, have a good evening.

I found one here: http://fallout3nexus.com/downloads/file.php?id=11474

But it needs a bit more work, it's quite static, doesn't look great and turns off when talking/using the pip-boy which rips you right out of the game.
But, it's a start!