By default Tabs Studio installs to a subdirectory in the user’s My Documents directory. You can install it to a different directory using following command:
msiexec /i TabsStudio_151.msi INSTALLLOCATION2008=c:\TabsStudio2008
You also need to add this path to Visual Studio 2008 options:
Additional add-in file path for Tabs Studio installed to a different directory
To uninstall Tabs Studio from a different directory use following command:
msiexec /x TabsStudio_151.msi INSTALLLOCATION2008=c:\TabsStudio2008
To update Tabs Studio in a different directory with a new version use following command:
msiexec /i TabsStudio_152.msi INSTALLLOCATION2008=c:\TabsStudio2008
To install Tabs Studio for Visual Studio 2005 use INSTALLLOCATION2005 variable:
msiexec /i TabsStudio_151.msi INSTALLLOCATION2005=c:\TabsStudio2005
For Visual Studio 2010 Beta 1 it is more complex as in this case Tabs Studio uses additional helper extension installed by default to a subdirectory of LocalAppDataFolder.
Tabs Studio Blog (organizing Visual Studio document tabs) 