Using custom configs other than (a couple FPS and packet tweaks that make the game run a bit smoother especially if you have a mediocre internet connection) on our servers is generally frowned apon. It gives an unfair advantage.
Using a custom config Promod Config that alters game textures beyond the stock (Low, Normal, High, Extra) will get you banned. If you are running around pwning everyone and constantly emptying the servers you may be removed. It's part of the admins job to keep the server population up and the Drama to a minimum.
Most people play with stock settings or just a couple of the following.This is all I use as well. Game never drops below 250FPS.
Draw your Lagometer on screen: /cg_drawlagometer 1
/cg_fov 80
/com_maxfps 250 (FPS)* Do not set it to 333. That is not allowed.
/snaps 40
These 2 maxpacket tweaks help a bit with lag spikes and lowers your ping by 10-15.
/cl_maxpackets 100
/cl_packetdup 2
/rate 25000
/r_multigpu 1 (FPS)
/cl_mouseaccel 0 (MOUSE)