Ok so I used to be a car audio/video/alarm installer quite a few years ago now. My brother got a 2008 HHR and we got him a Viper 5901 alarm system. I found out that now most newer cars have factory alarm interface modules so I found the one for the HHR and programed it. Now I'm getting ready to install it but I'm a bit confused and the instructions are not completely clear on what harnesses I need to use. I understand how to connect the 20 pin wiring harness from the bypass module which is the CANMAX400DEI but I'm not sure what connections I have to use on the alarm it self. Most of the harnesses for the alarm it self are remote start harnesses it seems which I'm not sure if I need to do that as there is a factory remote starter available for the HHR so I figured maybe the factory alarm interface will handle that as well? Or maybe I'd be better off just doing the aftermarket remote start install anyways? It looks like there are 3 different remote start harnesses and then a door lock harness. I'm 90% sure I don't have to use the door lock so I'm just not sure with the other ones. When I was installing before we didn't have the factory alarm interfaces we had to do everything the hard way so I'm just a little confused as to what exactly the interface is going to take care of and what I need to do with the alarm brain.

Thanks for any help in advance!