I have always put a bright red, flashing LED in all of my cars so it looks like I have some type of super alarm. I get them off EBay. Here is a link.
http://www.ebay.com/itm/Varad-LL-107...e53d63&vxp=mtr
Follow the instructions and you can wire it so it turns on when you turn the key off and turns off when the car is running!
Walter Duane Robinson Phoenix
Walter D. Robinson