What would be preferred? A siren with a backup battery inside or a siren wired into the backup module? Is there any advantages or disadvantages for the two?

 

both. you still need the back up battery to power the alarm and keep the kill switched activated.

 

The back up battery siren needs to be in a location were you can get to it with the key if you need to turn it off. The disadvantage of this is the fact that it will most likely be easily accesable by a crook who can muffle the siren with a rag or just unbolt it and run off with it against their chest (you can barely here it when its muffled). I still think its a good choice for an added layer of security as the crook will have to do something with it.

If your gonna get one or the other definatley go with the Back up battery. It can be installed inside the car in a secure location and will power and trigger the alarm if the main battery is disconnected. This is preffered as a theif wanting to get your car with an alarm will most likely start under your hood killing sirens and disconnecting your battery.

My personal preference is to add additional standard sirens in odd places like rear quarters, under a seat, or even under the car then hook those up to relays on our back up battery system so there is all kinds of racket when they try to disconnect your battery. (Though I don't recomend this I have hooked them up to Fog Horns and believe me that will most definatley get anyones attention when triggled)

Let me know if you have any other alarm questions. I love tricking out alarms.

 

Nobody said put the back up siren were a theif can get to it. There are nice spots in the engine bay were it can be put and still gotten to with the key.