OK, here is the deal on the 3660 I received with NO 3.5” SATA Drives installed.  The PSU is Modular in that the power cables for the drives do in fact plug into the PSU.  While the PSU is the kind that runs on the bottom and not your conventional ATX Shaped PSU it did have Modular power cables which can be plugged in.  There are only two slots for 3.5” SATA drives and while my build had no 3.5” SATA drives installed,  the caddies were there as well is the power and SATA Data Cables which were run to the Hard drive slots as well.  My only disappointment was that I thought there would be 3 places I could install 3.5” SATA Hard drives but there were only two places.  The Mother board has 5 SATA Data ports. Thank you all for your input!
  I am anxiously awaiting my new 3660.  I ordered it without Sata Drives, just the 2 SSD drives as I have three storage Sata drives from my old box I plan to use for storage.  My old box was home built and definitely legacy built on a LGA1155 Motherboard package and technology has changed somewhat.  I am beginning to realize I am not the expert I once was.   I just need to know if the Sata data cables and power cables will be there for use or do I need to supply the data cables.  I guess another questions is the Power Supply Modular or do I need to power the extra drives with serial connectors?  All in all I guess I am wondering if I need to be ready with data and/or power cables for the three extra drives I will be adding.  I can’t wait to finally have really really fast email!  Hehe….
Precision 3660 adding Sata Drives