I'm having trouble getting all the bugs out of this thing, Ultimate Electroncs says the factory alarm and the matrix 2. 1 are not compatable. When I open the door after disarming the system sometimes (about 50%) the factory horn goes off, this seems worse when outside temp. is cold. If I look in the window and the light is flashing then I know to put key in door and disarm so horn won't sound. This is on an 03 with factory keyless. I see DEI makes Viper and Python, and all appear to be the same. I'm about ready to pull it out and forget about the starter and cool down. Anyone having the same problems?