Just get an alarm, put the indicator LED somewhere in plane sight when you look in through the drivers side window, take your faceplate inside at night, and keep the inside spotless/ or a little trashed up but with absolutely nothing valuable in sight. I have to park in a parking lot an all I got is a viper like 5002 or something. No window tint whatsoever, never have a problem and there have been a couple cars stolen the past year. Knowing there is an alarm to a crook is like knowing your going to get some kind of std from that hooker, it just dont make sense to go through with it.
Plus with the 2-ways you can at least know when your alarm is going off and not have to run outside everytime you hear that familiar siren in the middle of the night.