CAT5 straight through does work, but you must check the pinouts to make sure it's a passthrough, pin 1 goes to pin 1, 2 to 2, etc. So you'll most likely want to crimp it yourself.
Plus you can get all the hip new designer CAT5 colors and color coordinate for the occasion!
I gotta crimper and tester if anyone needs to borrow. I used to do that for a living.
Its all going to be run where it can't be seen. The only things visible will be the head unit, the mic, and my CB.
That is how I attempted. I tried to use some "SAFCord" but my carpet wasn't loopy so it won't stick. and I am too lazy to fish the wires under the carpet. I might just put all the cords through the plastic conduit stuff.