You can delete the \support & \upgrade folders and setup.exe & autorun.inf from the dvd root, also you can delete ALL the files in the \sources folder EXEPT: boot.wim, install.wim, *.clg (of what versions you still have in install.wim) and setup.exe (its REALLY IMPORTANT that you keep setup.exe in the \sources folder, you dont need the one on the dvd root)