Trying to install some items (horns, etc) which will require some wires going from the main cabin through to the engine compartment. I see many posts on air horns and extra lights, but I have yet to see anybody post the picture on how to get the wires passed through. My previous cars I have...

I just completed installing an upgraded audio system in my 2008 RTL. I am (was?) a complete newbie to car audio installation, never having pulled off any interior panels or wiring before. I was always afraid I would break something or create rattles or cause some electrical issue. After...