For 6 drives (one being 2.5"), you would also need an eSATA to SATA cable. For 6 drives, all being 3.5", you wouldn't use the IB-168SK-B (you'd use an X-Swing or equivalent). I can't remember if it comes with a SATA cable, but that should be listed on the Icy Box or supplier web site.
2GB would be enough to run unRAID plus some add-ons. SABnzbd and cache_dirs can both use a lot of RAM, so I'd put in another 2GB or 4GB myself if you wanted to use both of those. Or try it first.
Use an N40L compatible BIOS (I think one has been posted on avforums).
Thinking of going for the 6 drive option, all 3.5. For this, I would use the spare sata for one of the drives up top, but what about the other? Still use eSata to Sata for it? And would I have to have the lid removed to fit in the drives and keep them cool enough?
All the information you have asked about is in this thread. I'm not going to keep answering the same questions over and over when I've already spent a considerable amount of time writing up how-tos.
Someone with more patience than me might want to do that, but I'm going to suggest you read the entire thread. Or at least skim it. Or just look at the pictures.
OK I've read the thread for the third or fourth time, and I think I have a good idea now of what I would need. I understand where you're coming from with the annoyance at people like me asking questions, and I'm hoping I'll be done after this. But I do have a couple of things that I don't know for definite after reading everything again, and I would just like to double check.
My current plan is to fill the 4 standard bays obviously, then add 2 3.5" drives at the top, and a 2.5" cache drive as well if possible. The microserver as I understand has one extra SATA port, that requires a BIOS mod but is fine for 1 of the 2 3.5" drives at the top. There is an eSATA port, perfect for the 2.5" cache drive, leaving a need for one more SATA port for the 2nd 3.5" drive. For this I aim to buy a Rocket 620 (http://www.scan.co.uk/products/highpoint-rocket-620-(r620)-2-channel-internal-pci-e-v2-x1-to-sata-6gb-s-non-raid-controller-card) and a Nexus Double Twin (http://www.aquatuning.co.uk/product_info.php/info/p6594_Nexus-Double-Twin-HDD-decoupling.html)
The next thing I'd have to buy - cables. This is the area I have the loosest grip on at the moment. I'll need 2 SATA cables for the data transfer (although I think one comes with the microserver?) but what about power? Will cables that come with the drives suffice? Or will I need one of these to power the 2 drives up top? (I think I will) http://www.amazon.co.uk/Molex-to-2-SATA-Internal-Power-Splitter-Cable/dp/B0002GRUV4
Finally, the lid. I've read speculation in this thread about whether it would be safe to leave it on with 2 drives up top or not, but no definitive answer. I would rather have it on but obviously won't if it would endanger the components.
Sorry again for the questions but I don't want to buy things that I don't need, or not buy enough! Once the build is done I can start getting my hands dirty, and hopefully will learn much quicker then Thanks.