I didn't even read the rest of the article, and just was hunting through everyone's info for the infoirmation I needed. I went back and read and his placement of the switch is ideal, and his workmanship is nice and clean for it. I had to go a different route. Basically to turn off my car, the reverse light on the driver side will have a big "OFF" and a lightning bolt, then you will see a plunger switch coming out of where the reverse light used to be. Then I'll just have a single reverse light on the passenger side. (can't see anything with em anyway)
I think your idea would work. Do you have the 2 pole switch like I do? Or is yours the newer 4 pole that is actually meant for it? I don't know why they sell the 2 pole and say it kills the car, all it does is disconnect the battery, and then the alternator keeps the car running. According to the track rules, the switch needs to kill everything. I wonder if BMW owners with stock batteries in the trunk get away with not having all this.