Most newer vehicles run on a Data system that controls many features of the vehicle. You will need access and the hardware to program either a idata, xpress, or fortin module. The firmware will provide a data immobilizer bypass, arm/ disarm oem alarm, door lock control, etc. You could install the avital and have a shop install just the module for you if you are looking to save some money. But, i would not prefer that method at my shop bc that just adds another complication if the system does not functiom properly. There should not be much of a charge on this install, i can complete these installs in 2 hours with soldered connections.
Since you have an avital you would prefer to use an xpress kit bc it will run through D2D mode
http://www.xpresskit.com/product.aspx?productid=461 . In D2D mode, you would only have to connect the module to pin #2, purple on the oem obd port
I've purchased the same 4103Lx system and hearing I need to buy a directed electronics PKALL xpress data transponder (per amazon, automotive genius ?) to install or have installed in my 2004 avalanche 1500. Anyone confirm that's all I need to provide the install shop or another kit to make it work? appreciate help. Sully67