hello, i just got my new mac pro a week ago. am planning on buying 2 500gb drives to store data. 2 questions: 1) should i just buy the OEM versions? will i need a cable or anything that is included in the retail box? 2) do i need to get any special hardware or software for a RAID setup? i didn't get the RAID option when i ordered my computer. i just want a redundant copy of all my data on both drives. maybe i just need to manually backup the primary drive to the second drive? thanks.