Backup your original files first.
Then,select the audio file you want to replace.
Let's say it's name is 123.wav
Now,select your new audio file (Note:It must be a wav. MP3,wma,MP4 etc etc don't work.)
Change the name of the new audio file so it's an exact match with the file you want to replace.
Delete the old one,put the new on it's place and voila.
How do I change the audio effects?
Not just for weapon fire, but for stuff like incomin missle alert, shield fail etc. I can't listen to the audifiles since winamp refuses to play em (too short I think)