Hey Cameron,
If your goal is EIB, you should definitely check the EIB specific requirements before doing all that work on the eFX. It's a nice, affordable helmet and I own two myself, but I don't think any amount of modding can make it EIB accepted. I was looking at the EIB requirements last week and I'm pretty sure it states that no MRCE or eFX helmets are accepted.
I ended up getting a CAP helmet and I have to say I like it a lot better. The one I got already assembled, painted and ready to troop was only a little more than a new eFX bucket. If you're willing to build it yourself you can even get one for much less.