[blue68f100]

I do not know about the scsi card, but the SATA is plenty fast. You can not tell any difference between the local 4500 drives or S10. There is a single controller card in the S10. It uses the same sleds as the 4500. The options for the S10 are Raid 0, 1, 5 or global spares. Now on configuration you can have seperate shares (safest) or span the share on the 4500 (main unit). But if you span or use it to expand the Raid5 array (7disk array, 1 spare) and the S10 goes down you loose your data. So it's safer to use it as a seperate unit.

There is no power switch, the unit is fully controlled by the main unit. Adaptec warns you, not to use a SCSI cable with the SATA card. They say they are different. I have not confirmed this.

btw, it has high velosity fans in it too.