mine sits one the firewall.
middle top of image.
pump you can put anywhere. mine is actually in the stock spot in front of the strut tower drivers side.
I have since revised that bracket to a early 90s maxima one. it sits on the strut now.
costs - not really relevant. all of it will be secondhand from wreckers.
auto and manual ARE different electrically. if you are going to pull one from a wreck make sure you grab everything attached to it.