Im basically aiming for a switch I can mount somewhere which wouldnt allow anyone to start car of steal car unless switch is turned on. Ive seen it done before just wanted to see if anyone has tried it or any experiance with it?

 

I have 2 actually, one fairly obvious yet still hidden and another that you'll never find. I bet a lot of people have done this, but wouldnt say where at.
I have 2 switches wired in series.

Another idea is a spring loaded spdt switch wired to the starter, so you have to hold in button and turn key to start. I think I may do that. A bit of overkill never hurt.

 

So wait what is yours wired to can you give me an idea on how to do this? Also I thought about having one fuel cut off switch and one electrical what you think?

 

it's good to wire kill switches to something simple just as the earth to the ignition barrel ecu, also, be careful it doesnt mess with stuff like alarms or imobilisers which it's off.

 

The clutch engagement switch, ECU ignition feed or any feed to a required fuse will work. There are many fuses that will disable the car if blown or removed. You can wire a disable into one of these circuits or simply remove key fuses or relays when the car won;t be used for extended periods.

I wired a a kill circuit in an older car years ago that kept my ignition open until a wire was grounded. I attached that wire to the back of an interior screw that atttached to a plastic panel and didn't provide the necessary ground. When I started the car I touched the ignition cylinder (ground) and my other hand discreetly touched the screw that needed ground which allowed my car to start. I had a hidden valet switch to disable the kill in case I valet parked, needed service or lent the car out.

Be creative, it's only DC.