Has this been tested with blackout+force speed I know the mechanics are the same but just curious.
Not sure I follow you. Blackout provides the same stealth level increase as sneak. I forget what you can push your stealth level to as a deception assassin, but I would guess about the same. Force speed is usable in stealth without breaking out of stealth, so yes it could be used the same way exfiltrate is to get close before being spotted