New Studio XPS 8100 -- is it okay to add drives before initial power-on?

I just bought an SX8100-959 w/ one HDD and one optical drive (DVD+/-RW) and haven't even powered it on yet.  I have already inserted an additional 2x2GB RAM to bring it to 8GB, and I also want to add a second 1TB Seagate Barracuda and an LG BD-R optical drive in the HDD1 and ODD1 slots, respectively.  I have two questions:

1 - Is there any problem with adding these things before ever powering up for the first time?  Is there a pre-set Dell initialization that will get fouled up on first boot when the OS does its initial setup, or will it recognize the new drives (provided I've enabled them in BIOS) like any other time?  [My reason for doing this is to have a complete initial setup and have the drive letters in the "right order" ... e.g., C & D for the HDDs and E and F for the ODDs).]

2 - Will the 350W PSU be able to handle the 4 drives if they were to be all operating at once?  (This unit has the 1GB Radeon 5450 card.)  What are the symptoms of an overtaxed PSU?

Ok - one more question:

3 - Does it make any difference which SATA ports I plug these into?  Is there any optimal configuration based on interrupts or addressing?

Thanks!