8) Well sort of answering my own question:
Officially largest drive supported is 2TB: en.community.dell.com/.../20364591.aspx
Unofficially someone had gotten 3TB drive to work by installing Intel drivers:
en.community.dell.com/.../19831550.aspx
New question:
Will this configuration work: 2 TB boot drive + 2x2TB drives in software RAID1 + one more 2TB drive for non-critical data?