This sound pack is highly recommended
Changes the sounds for the imp, the pinky, the zombie, the fat zombie, the zombie commando, the hell knight, the pistol, the shotgun, the machine gun, the chaingun, the player, that's it!
http://www.ggmania.com/?smsid=16599
"This is the first "Real" trick/frag movie for Doom III. It includes; Single tricks, Team Tricks, Frags (airrockets included :D)
http://www.esreality.com/?a=post&id=725377
UPDATE*
Tweak-file has been updated it's faster then org-tweak and it also removes those artifacts.
http://esprit.campus.luth.se/~humus/temp/doom3PerformanceTweak.rar
I like it. I haven't found the chainsaw yet so zombies are annoying since they return from death, but thats how it's supposed to be. It's fun to use the shotgun now because enemies fly back much longer.