Lo jack! or plumb in a plumbers ball valve with the handle in your fuel line to the rear with the handle up thru the floorboards under the Dr seat. When you park turn the handle 1/4 turn to shut it off then if they are able to hot wire it it'll go a block then die in the middle of the street & they'll have to vacate ASAP rather than draw attention to themselves. other wise without a setup like that if they manage to get past whatever alarm system you employ once its running it is GONE. JC Whitless in Chicago used to sell a solenoid that would let you do that (open/close fuel line) with the touch of a button in the dr seat, that woulda worked if you keep the button/wiring hidden & even if they did see it in their panic they might not realize that it is a fuel prob & that that button is a bypass. I'm sure someone would have the parts to duplicate that system