Q: Do you need to use all 3 PCIe connectors?
A: I would stick with 3 per hashing board.  They make sure in email, and in a paper in box to tell you to use 3 PCIe per hashing board. You might get buy with it but it would void warranty.  I would say depends on gauge wire and quality of psu.  But to make life easy and in warranty stick with 3. Bitmain has made sure to tell us only use 3 not 2 with this miner in posts at this point.

Q: What version of cgminer is being used?
A: On my miner which is running the stock firmware that it was shipped out with it shows cgminer 4.8.0 being used.

Q: How many amps do I need to run this machine?
A: Bitmain is very specific on the paper sent with miner you will need 16 amps or bigger to run.   This is where you get into variations of installs as there is a few ways to achieve this.

Q: What about the heat?
A: With the metal case and a push/pull fan setup Bitmain did a very good job on making this miner better then the regular S5 on heat.  It still does have heat with the amount of electricity.  But the metal full case with push/pull compared to plastic S5 sides and no top with just push fan is a noticeable difference.