I wired mine with the ignition which was easy to do. I've put them on with the bumper off as well because I needed to take off the tint from my fog lights. You might need an extra hand with taking the bumper off. I did it by myself but it was a little tough!
Thanks mike! Your xb made me really want to get the lowering springs. And it's also the first time I've seen the trd exhaust on an xb looks great! Did you put on the vent covers yet?