The tfish_mech_upgr_mod.zip file you have requested: Modifications / Single Player / S to T Titles / Mechanic Upgrades MOD (1.0) - 13.2kb is not available. Perhaps try browsing all files for the game S.T.A.L.K.E.R.: Clear Sky and upload any files you want to share or are missing. This is the only information we could locate:
INSTALLATION============1. Replace the the file: gamedataconfigsmiscstalkers_upgarde_info.ltx in your ClearSky folder. On my Vista machine I use the following path:C:UsersDixonAppDataLocalVirtualStoreProgram FilesDeep SilverS.T.A.L.K.E.R. - Gives all mechanics access to all upgrade types... Well, most of them! I am sure to have missed a few but, now that you know how to, you can add any that I missed as you find them.