I am not sure if RAD Studio from 2007 to XE6 are using same type of installer to package. As end user of RAD Studio, I always run Setup.exe in RAD Studio and perform the installation by selecting options from the wizard dialogs page by page.
Is there any options in RAD Studio installer that may perform the installation via command line only without GUI dialogs?
Some useful links regarding silent Delphi installs, not really an answer but what I found doing my own research
http://delphisorcery.blogspot.co.nz/2011/07/unattended-delphi-installation-how.html
Has some notes on some of the command line parameters - still need to supply the license however
http://edn.embarcadero.com/article/29900
This article indicates that silent installs are not possible (not sure of its age however)
http://docwiki.embarcadero.com/RADStudio/XE6/en/Installation_Notes_for_XE6
XE6 release notes, doesn't say anything about silent installs
https://forums.codegear.com/thread.jspa?threadID=64992
A post for silently installing Delphi XE
http://www.msfn.org/board/topic/137195-codegear-rad-studio-unattended-install/
Another post about silent Delphi installing