EFI guys, any options for theft protection?

There's a bunch of ways you can do this, Dion, depending on the equipment at hand. There might be a wire in the ECU you can ground. If you run an MSD 6 you can ground the white wire. Otherwise, just put a switch, "not obvious" does not even really need to be hid. On a Holley just series into the main EFI power relay coil, or the pump relay coil. There are other ways.

I plan to run a trunk mount battery. There's a couple ways you can kill that.........aren't you running some sort of electric latching relay deal?