I too use older sounds. I just save a directory of old sounds (b20?,guns) I've cleaned up a bit. Then when I install a new version, I just replace the respective folder. It's not like it's hidden or complicated.
Although my sounds are modified stock, it's for sounds quality purposes only. In fact, I'm racking to figure out how sounds could be used to an advantage. About the best thing you could do would be within the code itself, which is obviously restricted. Manipulation of the files wouldn't gain you any more advantage than they offer so far, as much as I can tell. I wouldn't worry about a run of sound modifiers in the "Cheater Reports and Bans" section.
If you're interested in the development of the sound files you can watch this slow moving and sporadic thread,
http://dplogin.com/forums/index.php?topic=15019.0;topicseen, of which I enjoy participating. Most of posts are based around the "why" of the idea that many old sounds are preferred. Please try not to post unless you've got something productive to say, and not "I don't like the new sounds!". As contradictory as this seems to my other recent threads, I'd prefer to have this thread stay focused on very relevant applicable post's, and definitely not have it locked from silly statements.
If you still need some older sounds, pm me and I'll send you the directory (despite how much you annoy the crap outta me on irc....).