A friend of mine has got a bit of a problem with his network storage. They are running on a Terastation with 15+ people in a print/design shop, it's creaking to say the least. Looking at the options it's been recommended to go with a Mac Pro and get a SAS card and external enclosure. Is that the way forward? What can people recommend to me for someone who needs 3-4TB of usable space? Any specific raid cards + external enclosures?