This is all refering to the wiring from the pump to the harness inside the tank


when putting on the pump I assume the black wire replaces the black wire and the white wire replaces the grey?

It talks about how it replaces all the wiring, but there's not one to replace the purple one, so I assume you just leave that there?

 

White = + replaces gray
Black = - replaces black
Violet has nothing to do with the pump. It is the level sending wire. Leave it alone.

Remove the factory terminals with the pin / clip supplied and lock the new ones in place. Replace the gray terminal lock and the orange connector lock.