Rez files control every aspect of the game, but there are some things that cannot be changed because they are "server sided" which means the folks at z8 games are the only ones who can alter them. Among the "client sided" rez file mods are .....
possible to change......players colors, clothes, guns, skins, maps skins,textures, rate of fire reload speeds, etc of weapons, special effects, such as namecards, or whatever they are called. Pretty much anything you see from your end ,except for the EXP points, GP, ZP, and kills, can be cahnged through REZ file modification, just too bad noone has a tool to do this with.............yet