Questions about custom models

I did some reading and I probably missed it, so I thought I would at least ask. I'm definitely interested in making and importing custom models/textures for myself and a handful of friends, but does the current NS2 setup allow this to happen? I ask because I remember how in NS1 players could create and load custom skins, sounds, etc without requiring the server to accept or host them.

Thanks. And no, it's not stupid BS stuff, just stuff like maybe stuff from aliens or mass effect.