I was going to post this in the group buy thread, but bobsag3 locked it. I hope this is helpful for those thinking about exchanging for bare chips.
Fisrt of all, paying for assembly with chips is a pretty good deal. You're getting a value of $69.75 per chip from Technobit. Much better than the $35 or $25 others are offering. Who are the vultures?
Assuming 1 X3, that's 100 chips. You end up with 12 boards, with four chips left over. 8 chips per board - that's 4 in the board, and 4 for payment.
So a grand total of 4.8 TH consuming ~4800 W.
Additional costs include coolers for each mounted chip, so in this case 48 coolers. Any socket 1150 cooler will work, but it needs to dissipate 100W. Also you'll need ATX PSUs to power them. In my opinion, I'd go with 12 500W units rather than powering multiple units with one PSU. The 1000W+ PSUs get proportionally more expensive. 500W units are much more common and cheaper per watt. YMMV.
So I found some 100W coolers for $10 a pop. If you want beefier ones, you'll pay as much as $25 a pop. So between $500 and $1200 for coolers.
I also found a well reviewed 500W PSU on sale for $25 after MIR. But you can easily find them for $50. So between $300 and $600 for PSUs.
So let's take a middlish price and say $1200 in additional out of pocket expense for 12 boards, or $100 per board to get them running. Plus you still have 4 chips which you could have mounted on a 13th board for $279.
So you would end up with 5.2 gh/s for an extra $1600. That's about 60% more hashing power. Is it worth it, or is it throwing good money after bad? You decide for yourself.
After MIR price is only useful if you are buying a couple since almost no MIR will let you get a rebate for 12 units. You'd probably be better off (and get a much better supply) if you bought four of Sidehack's DPS-2000B boards with cables for $366 along with four PSUs off eBay for $120, and ran four boards off each one.