Proxycotyl

Has anyone else had an issue where their crysis suits Interface just dissapears?

I just installed this mod and whenever the character has no clothes on the texture looks messed up. He has abs on his arms and his pecs don't even look like they're there. It may be because I have that skin added in, is there a way of fixing this?

How do I install a body replacer such as the Hgec? I can't figure out where to put those Nif files.