ok, k-otic posted something for q4 but i found another way - at least it works for etqw:

i assume youre working with the sdk...
open /framework/cvarsystem.h
in class "idCVar" right beyond "static void RegisterStaticVars( void );"
change the "private:" to "public:" to make the variables writeable from whereever you are.

now just do something like:
cvarSystem->Find("pm_thirdperson")->integerValue=1;

booya! this way the cvars seem to be unchanged to punkbuster, servers, console logs and stuff but the game uses your changed values

- FSH