Well lit parking space, nose first, wheels cocked w/parking brake, Police Athletic League t-shirt & Glock holster laying in pass. seat, NRA window sticker, fuel and ignition cutoffs, Alarm siren w/ batt backup buried out of reach. Bare minimum of blinking red light on/near dash/console (cell phone charger with a tissue over it). FCC regulated 3 watt max Paging alarms tout up to 1 mile range on a totally flat and unobstructed surface but rarely penetrate malls/parking ramps. Cell alarms (calls your cell phone) offer excellent range and penetration but are relatively unheard of yet on this side of the Atlantic save one crude newcomer;
www.bustthem.com. GPS anything is only as good as its obvious antenna...first thing a thief pulls off.