Ok, looks like I just misunderstood what you were trying to convey (as well as some others). I thought you were going to go with a single large un-approved eSATA drive (using the Seagate in your own enclosure). Anyway, I'm glad it all seems sorted out, and nobody got hurt in the process. So, are you really going to leave the stock drive in and buy an approved expander (which nobody who has ever used one would ever recommend), or are you just going to get a 5400RPM "Green" (Preferably WD AV-GP, or Seagate equivalent) drive that won't give your power supply fits? I can say that I've used 3TB WD Red NAS (AV rated, green power profile, 5400RPM, 3yr warranty) drives in my three base Roamios, and am certain the wall-wart power supplies would overheat if without lots of air-space around them (the Red drives have the same power requirements as the Green do, so it's not due to the color-coding). Others have reported using Seagate 7200RPM drives in base models without any trouble, which makes me wonder if your power supply is "up to snuff". Perhaps if you could supply the specifics of your drive's spin-up power requirements, we could help figure out "what's what". A good start would be just the specs printed on the top of the drive say for amps. The spin-up would require the datasheet for the particular drive model. I'm just trying to save you added hassle/time/frustration, if I can.