Alarm/keyless entry questions

[jermasaurus]

Hey. Been away for a while. Computer problems, motor problem. So the my computer is fixed, and the truck has a new motor.

Now I have an alarm and keyless entry I want to install and have a few questions.

First, does anyone know if the door lock system is a "positive trigger" or "reverse polarity"?

I guess thats the only real question i have. But can anyone post pictures of where they either installed the box or where they made most of the connections?
Should I just splice into the harness right by the junction block at the firewall?
Any tips? This is the one i am installing. http://www.crimestopper.com/index2.html
It was given to me, so thats my reasoning for the model I am using.

Thanks
-Jeremy