What kill switches are you trying to install and why?
Have you considered a decent alarm system - much easier than multiple kill switches.
If you do go down the switch path - you'll want to cut ignition and fuel.
Igniton can be found under the steering column - you'll see a connector with usually 4 heavy gauge wires coming from the Igniton barrel. Unsure on the GR's but the GD's are either solid white or white with black trace for ignition cut. I'd recommend using a relay to break that one unless you have a switch with 20A+ rated contacts.
Fuel for the GD's there is the relay located behind the passenger kick trim. You can cut into that circuit like the alarm systems do - or try locate it around the fuse box area.
In all honestly for the headache I'd just get an Autowatch fitted. Cute fuel and Igniton really easy and without the messing about.
Sent from my SM-N976B using
Perth-WRX mobile app