Anyone have an internal drive expansion unit for their G5?

I'm considering buying a mac connect internal hard drive connection unit for my PowerPC G5 and am trying to figure out what is needed to install 2 TB drives in this thing and whether I need to use RAID system with new drives. I've tried emailing/calling manufacturer but no reply yet. My system admin person is going on vacation at the end of the week and I need to order asap so am posting here.

System offers an aluminum case for up to 3 drives, SATA cables, power cables, fan, PCI-X cards with 2 or 4 ports.

For adding 2 drives do I need PCI-X cards with 2 or 4 ports (what does this mean)?

I already have the original 250 GB drive in the machine and an additional 500 GB drive that I added about a year ago. If I add 2 more TB drives this way do I need to use RAID on the 500 GB + 2 TB drives? If so, at what level? Do I need additional hardware for this or is some sort of RAID software enough?

thanks for any help. most people around here have PCs running Linux!

oops! does this question belong in "Other Hardware and Perifs"??