I always prefere the original packages - but thats just my opinion - makes its easier to keep my DVD up2date. So
Firefox_Setup.exe -ms
does the job. As for the Quicklaunch icons or start menu entries i run a simple cmd afterwards to delete/create a shortcut to wherever I want, e.g.:
"%userprofile%\Application Data\Microsoft\Internet Explorer\Quick Launch\"
As for the extensions/themes i put them all into one directory (i know, this is just a method to install the extensions, NOT to personalize them - and im not sure why i included the profile creation

- anyway, it works). When you run this from a cmd %e is ok - when you want to inlcude it into a .cmd you have to replace %e by %%e.
CODE
"%programfiles%\mozilla firefox\firefox.exe" -CreateProfile profilename "%userprofile%\Mozilla\Firefox"
IF EXIST "%programfiles%\Mozilla Firefox\firefox.exe" for %e in ("%cdrom%\Software\Firefox\*.xpi") do "%programfiles%\Mozilla Firefox\firefox.exe" -install-global-extension "%e"
IF EXIST "%programfiles%\Mozilla Firefox\firefox.exe" for %e in ("%cdrom%\Software\Firefox\\*.jar") do "%programfiles%\Mozilla Firefox\firefox.exe" -install-global-theme "%e"