Silvia-Cut off Switch???

[Hachihead]

Need to install one of these for the next event,as i didnt get round to doin it before the licence day.What i need to now is:

What wire/s do i need to have on the switch,apparently if i just cut the live feed on the nissan the engine will continue to run.
Is there an ecu wire i need to use or whats the story?
Car is s13 silviaAnd if so how do i know which wire to use?

Sound.

[Channie]

Hook to on your main power feed from the battery... connect the others as the instuctions... then hook the other one to the ecu main live... kills power to all the electrics... injectors coils etc.. dont know which one is the live on your ecu... if no one gets back to you by monday i'l have alook at one of the PS13s down here and let you know