What is the power consumption on this SP31?
When does the hosting finish?
They use like 3000 Watts. So unless you got cheap power, you might as well get an S7 since it almost the same price.
You are right cheap power is needed but don't forget that for an S7 you need to purchase the psu which is an extra 150$, you need to pay shipping and wait until mid-end December for Delivery
It would make sense if he was referencing to the people selling used S7 for about the same price, which they are in hand and ready to ship and already within the country, saving you much more than 150$ in import fee/taxes.