XPS 8500, Installing a SSD

I recently bought a XPS 8500 with a 1TB HDD.  It has Win 8 installed.  I want to install a 256 GB SSD and make the SSD the system drive.   I noticed that the 1 TB HDD was plugged into the first SATA port which seems to be a 6 GB port.  The DVD reader/writer is plugged into the second 6 GB SATA port.  I'd like to plug the SSD into the first 6 GB SATA port.  Is it OK to move the 1 TB HDD to the second 6 GB SATA port and move the DVD to the third SATA port which I think is a 3 GB port?

I also want to install Win 7 on the machine.  Can I get the necessary Win 7 drivers from Dell if I know the components in the box.  I backed up the Win 8 system to DVD's.  I guess I can use these to reinstall Win 8 if I want to down line, but If I should want to return to Win 8, where can I get the OEM Win 8 System Key if I want to get an OEM version from Microsoft?

Where can I get the other software that was preinstalled on the box?

Thanks in advance,

James M Driskell