you can change cvars any time simply by pressing the "~" key and typing:
/<cvarname> <value>
these new cvars will be available when the new patch is released, so yes you will have to update your game.
Some cvars are server side, some are are client side. Server side cvars control how the game reacts. When you connect to an online server, you can try to change the cvar g_gravity, but you will most likely get a message saying that the sever is not running on your machine.But, it you play the single player or create your own multilayer you can change g_gravity all you want.
The cvars you are currently using are stored in "*/Smokin' Guns/smokinguns/q3config" You can change anything there and it will be applied when the game is started. For instance:
/set name ^1Redwing
is probably what you will find somewhere in there. This just sets you name to
Redwing. If at anytime durrign the game you want to change your name, just type
/name <yourname>
Hope this helps