If you've never installed an alarm or rs system before, then have it professionally installed by a competent and reputable shop, or at least have an experienced fellow installer help guide you through the install. I've been installing for almost 20 yrs and have seen way too many bad installs go very wrong by DIY'ers and inexperienced "certified installers". I've seen a dash catch fire, thousand dollar pcm/bcm repairs and replacements, etc.
If you decide to tackle this yourself, make sure you have as much wiring info as possible and most importantly verify the info with a dmm. Wiring guides are not always correct, whether it's from DEI, Audiovox, Scosche, etc. And depending on your year vehicle, you may or may not need an interface for the locks and PLII/III system.
The best way to splice wires is solder and heat shrink. Crimp style connectors, especially Scotchlocks and t-taps are very unreliable, especially in an environment with constant vibration such as a vehicle. Not only can they come loose, but they also hinder performance because they cause more resistance to current flow, especially in higher drawing circuits associated with RS systems.
The 791xv is nice and is the same model I have in my truck. If you have heated seats, you can connect a channel to the seats. I have my aux channels wired to turn on my heated seats, rear window and mirror defrost, window roll up/dn, and headlight activation.
Feel free to PM me if you install the system yourself and have any questions.
