Ahh...i dont think you want my mod.
Its not just jetpacks i changed eg free battlesuits/chaingun etc its a 'Silly Mod'. You can change Jetpack sound yourself though its as easy as pie just go into the data pk3 copy the jet pack sounds then remake the folders
(C:\Program Files\Tremulous\base\data-1.1.0.pk3\sound\upgrades\jetpack\) Thats where jetpack sounds are
Make a new pk3 call it jetpacksilent or something.
Then in the pk3 youll need sound\upgrades\jetpack and in that folder youll want the modified sounds. Then put the pk3 in ur trem base folder. Note: thatll only work in servers you create or unpure ones.
But if you REALLY want my mod its avalible here:
http://files.filefront.com/K66Modpk3/;9199540;/fileinfo.html (just goto your trem folder create a new folder in there call it 'K66Mod' and put the pk3 in there. Then when you go ingame itll show up in mods menu)
(I use filefront(It Tracks downloads too))