the info from woeaintme is correct and first started in entrenchment, and the total number of upgrades in un-modified starbase upgrades is 24 for tec and 20 for both advent(psi) and vasari(phase), BUT the best way to do this is to create a mod in the mods folder the path can be found by clicking on the button labeled 'show mod path' in the options/mods area of the game, but is usually of these following locations
mods info
assuming you have sins 1.193/entrenchment 1.053/diplomacy 1.34(the current non-beta versions), AND your windows is installed on the 'C:' drive, the Mods NEED to be placed here for xp
C:\Documents and Settings\'user name'\Local Settings\Application Data\Ironclad Games\Sins of a Solar Empire\Mods-v1.193
C:\Documents and Settings\'user name'\Local Settings\Application Data\Ironclad Games\Sins of a Solar Empire\Mods-Entrenchment v1.053
C:\Documents and Settings\'user name'\Local Settings\Application Data\Ironclad Games\Sins of a Solar Empire\Mods-Diplomacy v1.34
or here for vista/windows 7/window8
C:\Users\'user name'\AppData\Local\Ironclad Games\Sins of a Solar Empire\Mods-v1.193
C:\Users\'user name'\AppData\Local\Ironclad Games\Sins of a Solar Empire\Mods-Entrenchment v1.053
C:\Users\'user name'\AppData\Local\Ironclad Games\Sins of a Solar Empire\Mods-Diplomacy v1.34
and for rebellion the path IS
My Documents\My Games\Ironclad Games\Sins of a Solar Empire Rebellion\Mods-Rebbellion v#.### with the #.### replaced by the current rebellion patch version numberand if you are using the dev, you NEED to place the mod in the ' dev' folder
NOTE the first two folders after the 'user name' are hidden , so to see them you must first click on 'tools' then 'folder options', then 'view', then click on 'show hidden files& folders' then click ok, then you will be able to browse your want to the folder. I suggest when you find the folder that you create a shortcut to it on the desktop
NOTE 2 the 'user name' in the above paths is your WINDOWS login user name, eg Administrator
note 3 these shortcuts assume your windows is installed on 'C' drive
and if the mod you want to use is from an EARLIER sins/entrenchment version place the mod in the mods folder FOR THAT version eg mods-entrenchment v1.03, then download and run my mods updater from the latest version archive which will have the same number as the vanilla sins version number, and AFTER updating the mod(s) to the current version for any mods of pre 1.04 entrenchment ALSO run the manifest maker on ENTITY manifests on EACH of the mods EXCEPT for total conversion mods
and inside the mod folder create a folder with the name 'GameInfo' (note the caps as the game engine REQUIRES this exact folder name), and inside the 'GameInfo' folder place your changed entity files ,the start the game and select and add your mod and enable it, the close the game and re-start it(the engine has weird issues if it does not have the files in during loading of the game usually resulting in a crash) and play with with the mod using all the upgrades for each starbase
harpo