Fuel Pump Kill switch
I used to have a Steeda 5.0 Liter Convt.Mustang that I didnt want my sister driving. Fords already have a safety switch in the back (automatic switch) that cuts off the fuel pump incase of a rear end collision. I turned it into a manual switch in the trunk. If you simply put a switch inline with the power lead to the fuel pump, I'm sure the wife would never figure it out. Also it would keep your factory alarm on and computer codes from reseting.
just my two cents