[spectheintro]

Yes, there will likely be a guide. Bricking your phone is always a possibility, but it's pretty unlikely if you follow the guide carefully and the unlocker is well-programmed.

Additionally, I don't think flashing from an SD card confers any additional benefit. (Could be wrong.) Basically, if the bootloader flash gets interrupted for whatever reason, I think you're probably SOL. But as long as the bootloader is solid, it's basically impossible to brick your phone, from my understanding of the issue.