You have to have a switch to cut power to both altenator and battery as well as an NHRA approved battery box vented to the outside. The bolts have certain requirements as well, mounting to the frame and closed loop etc. I have all the specs at the shop when you need them. Also, if you want to check out how mine is done, it is fully legal and looks pretty decent IMHO
The switch in the back is one of those things where design is somewhat important. If you have a switch clearly visable from the back that is always there, you might find your clever friends shutting off you electrical system in parking lots etc also, people who don't want your alarm to have power. I used a T-handle style that goes through the license plate area. The handle is removed when you are not at the track and the hole then covered by the license plate. The nice thing about it is that you can make another false license plate with a hole in it and the required signage saying "push off" for track use only. It works pretty well and doesn't give any clues when you are away from the track.
Hope that helps.