My 4 HDD bays are full... WD & SG. 1 optical bay open. What's the best way to get power connection to PCIe USB 3 card? Is the Optical bay my only choice? What kind of cable will I need? Probably going with Anateck, Sonnet or Anker PCie card. Seems their cables are meant for an open HDD Sata slot. Do I have to worry about Power Supply issues? Save for the 4 HDD's, an ATI 5770 VC and 14G Ram the Mac is a standard Quad.