I don't understand why everybody is so eager for these S6 upgrades. They probably will cost as much as a new S6 and buying 2/3x S5 seperately will be cheaper probably like it was with the earlier upgrade.
I'm not looking for an S6 upgrade... since there's not even a released S6 to be able to upgrade.
A lot of us are eager for an upgrade path for the S2, since it's been a great workhorse.
Probably... could be... I bet they.... is all speculation. Which is all we have at the moment. It might be costly, it might be cost-effective. So we're anxious to see exactly what Bitmain will have to offer.
Having said that, Pekatete has some great logic on the concept (and others).