Alarm DIY questions Audiovox Aps-500

Hi! Currently a new member here with a 1997 tacoma with no powerlocks or alarm system. I have some questions on my DIY project of installing the Audiovox APS-500 alarm system. I have gone through the wiring harness and labelled each wire for ease of connections later on. However, I am not sure where a couple of the wires connect to.

First off , I recieved a relay (Siemens VF4-4511) along with the package. The manaul states there are more than 1 applications that require this relay. So does that mean I need multiple relays (i.e flash headlights, interior light, beep horn,etc.) or is that one relay supplied enough for multiple connectons?

Secondly, I would like to make use of the starter disable function, but I am not sure where the "starter cut relay" is located at. Is it also really necessary to cut the solenoid wire of the truck? (Page 4 and 5 with the orange, orange/white wire of the manual)

Last but not least, is the "door trigger" on our tacos a positive 12 volt output switch when the door is opened or a ground output? Is the horn a +12 v horn switch? (Page 5 with the purple/brown wire of the manual)

Here is the manual:
http://audiovox2.info/docs/common/APS500/APS500_IM.pdf

Also, what is a fair price of a pair of powerlocks (OEM, aftermarket?) What should I expect to pull if I go to the junk yard (switches, solenoid, and...?).

Any input would be greatly appreciated, Thanks!