another good thing to do is to create a metal box around the siren so that it can't be destroyed, and yes hide everything VERY WELL... a pro theif can tear an alarm apart in seconds if it's not installed well... a back-up battery is nice too but not all alarms come with that... get one that works with the horn as well cuz the louder it is the more quickly a theif will leave it alone...
just some advice my friend at a alarm shop gave me... i'm gonna get the viper installed when i get an alarm... but i hear that A/C Delco makes the same thing as a viper (auctual same product) but with a different name, for less if you can find one.
