Does Touch play 24/96 files??? I know you're using digital out, is the BDA showing link to 24/96? That's great if it does. Shane brought a bunch of hirez files to our last g2g. They sounded awesome on the Gemme Katanas.
The purpose of RAID is safety, not size. Although a RAID array can have many drives in it and be very huge. RAID sacrifices one of the drives to gain redundancy against a drive failure. Any drive can fail and can be replaced with a new drive and the others will rebuild the new one with no data lost. If you lose two at once you're fucked. Maybe there is a RAID config that allows for 2 redundants? I dunno. Anyway RAID needs a controller to run the storage scheme. Maybe OS-X has it built in for local drives, or you can use a hardware controller PCI card, or a software app. Or buy a multi drive NAS that uses RAID and hang it on your network. The Netgear ReadyNas products are well designed. The newer ones have worked out the problems of the first models. It uses a proprietary RAID system that is easy and idiot proof. Basically you just stick the disks in and it figures everything out. Hot swap on failure, email notification of failure, print server, file server, runs slim server natively (slowly,) webserver, etc. Optimized for media streaming, like audio video playback, etc. I/O speed is pissa but it's not cheap. There are other brands making products like this too. D-Link has a small 2 drive RAID fileserver that's cheap. 2 2TB drives would give you redundant 2 TB in RAID1. DNS323. There are others out there, big and small.