Ignition Kill switch?

[Deathegg]

Hi Everyone!
I'm looking to install an ignition kill switch on my '10 Yaris hatch (theft prevention). I had one on my Festiva; a simple toggle switch wired into a low power coil wire, worked great. Engine would crank, but not start. (btw, No one ever found my switch that I hid inside the car, including someone I knew years ago who, at one time in his life, stole cars).

How would I go about doing this on a Yaris? Can I do a switch wired into the low power side of the ignition like the Festiva? This car is much more complex than the Festy was. Unfortunately I don't have a shop manual for the wiring diagrams, etc.

And, the simpler the better!

Thanks! :)