That's a cool mod!
@Benitomuso: If you need some more free .wav sounds for other purposes like breathing through a mask or anything else try this site:
For free .wav downloads you only need to register and that's it.
I don't know about the quality compared to real life experience but maybe you will find something usefull at freesound.org.
I have downloaded some from there and from other on-line resources, but I haven't found real good ones. Recently our friend Stratodog has recorded live very good ones specifically for this MOD and I will incorporate them soon. They will be much better than the current.
I'm investigating more in depth how to detect when a turret with motor is aiming, etc., so to use the sound only when it corresponds.
The only one I still miss is a good one for the empty shells falling. The one I used is quite ethereal and I don't like it.