Infernal we used to do this in the 5.0 mustangs all the time the toggle is the best thing ever. There is no way they can start it.
Pull the EFI fuse.
Wire in a hidden toggle switch for your fuel pump. (they'll be trying to crank it over for days!)
Along with this I also prefer to get it where it can't be cranked. Because, if they crank it enough you'll come back to a dead battery in which case then you can't start it either without charging the battery or at least a jump.
