How Do I Go About Adding a Factory Alarm?

[TechGuru]

What do I need to buy? What needs to be changed out?

Considering it already has the door sensors and key-less entry I assume it's just a matter of adding or swapping a module?

 

[TechGuru]

*bump*

If it is just a matter of adding a module does anyone have the part number?

If it is a matter of swapping a module what is involved with that, will there be a VIN mismatch triggered in the main ECU if I were to get one from a junkyard?