Also u have to remember that if u open the door/trunk/hood without disarming the alarm the car will turn off right away.
I have a DEI with battery backup and 2 siren with buildin battery and also a secondary wireless immobolizer that cuts the fuel (it replace the fuel fuse with a wireless one) is hidden plus a hoodlock .. . .
for some reason the remote has better range in the winter.

I have the matrix rs3 and even with the right key inserted after u disarm the alarm u still have to press 2 button on the control at the same time or the alarm will arm again. ofcourse in valet mode is a diff case.