You can't.
Yea support for SS basically died when the bootloader unlock became available. You may still be able to download some on xda or rzr but they will be outdated.
Sent from my Eclipsed Moto X DE
Yea you're correct. If my post wasn't clear I was referring to SS Roms... If you haven't unlocked you can not unlock but some old SS roms still exist. Most will be 4.1.2 and outdated.
Sent from my Eclipsed Moto X DE