I used to live in NYC. Car alarms are a waste. No one hears them and comes running anymore. If you're lucky enough to hear your own and get out there in time to stop the theft, you're faced with a different set of issues.

I used to make sure not to leave valuables in my car. I also had an ignition shutoff switch instead of an alarm. They could break in but not take the car.

Look around, try a car audio shop they usally do alarms too. They now have systems that will alert to your key fob, so you know when its happening. Also tint your windows. One they can't see in. Two makes it harder to break the window.

3 leave the ghetto.

4 If you got the money, replace all windows with polycarbonate bullet proof glass.

It's been a while since I've done any car alarms, but my old advice was always buy a directed electronics system (they have several brands under their umbrella including viper and clifford). Depending on your vehicle, there might be some additional modules you'll have to buy and usually those are only supported by one brand. Also, always get the glass break sensor. It's usually $20-30 and will detect glass being broken and metal being pried.

You can get fake dog shit and like plastic crud like gum and stuff. Stick some of that on the center console and dash and it'll discourage people from wanting to go in your car. Cut some spare wiring harnesses out of a junk yard car and dangle it under the dash as well. Stupid people are afraid of exposed wiring.

Lock your doors.

If someone wants to break into your car, they'll break in.

Stay away from areas where there is high probability car break-ins will occur. For example, where niggers are.

Drive a piece of shit or econobox, don't leave valuables in it, don't lock it, don't leave your spare keys in it, don't let trash accumulate (Starbucks cups, etc) because the will think there might be change in your center console or on the floor. Take the fuel pump relay with you if you are worried about it being stolen.

Nice vehicles indicate you have money and things. In their frustration at finding nothing of value they may still cause damage. Driving a shitbox, they have low expectations of what valuables lie within and so the shiny vehicles look far more interesting.

1) get a stick shift. 2) keep your car empty, not even cough drops in sight. 3) ignition switch, and hardwired dashcam. 4) keep your car clean. 2x they failed to steal my car and left behind fingerprints.

Park under a camera.

A manual transmission.

It's been said, but my vote is that alarms are worthless (completely ignored). Maybe the 2-way pager systems IF you're willing to toss your life over a confrontation, knowing that you'll be made an example of in the court system after the fact.

You have to make yourself not a target. This is accomplished by not having the nicest vehicle on the street. Not having Anything in the vehicle, including trash... nothing. No tinted windows either, you want them to be able to Easily see there's nothing inside. Use a stock (or walmart special) headunit, something thieves know isn't worth the effort. Sadly, it's cheap and easy to get replacement faceplates for those that are removable. I've even heard people talk about leaving doors unlocked so the windows don't get smashed. You do need a smartly integrated kill switch though.

I know, most people tie their identity to their vehicle and want the nicest they can get. It's just a bad thing to do when you can't protect it appropriately. I was motorcycle-only for a decade and road around on sub-$1000 bikes because I had to park in shitty places. Worst I ever had happen was kids playing on them and get knocked over, not a big deal, and I lived in some shitty ass hoods while coming back from homelessness.

And forget the manual trans BS. Watch some bait car vids on jewtube and you'll see the thieves actually like manuals better.

My car alarm is my garage out of the city. I suggest moving away from the crime, not trying to detect crime using an alarm.

Try to find an alarm that will alert you on your phone rather than make a lot of sound no one will pay attention to. Then you can go outside and goodify someone.