I got a new Uniden Pro 520 and plan on mounting it between the sunvisors. I have a Rugged Ridge overhead storage unit that I reinforced for the CB.
Ok so here's the question....I plan on the typical behind the spare tire mount (I know its a bad position) so if I run the antenna wire along the roll bars is there going to be a downside (interference) to that or should I run it under the carpet?

Any insight would be appreciated.

 

I mounted mine in the same position as you. I ran the coax across the windshield and into the roll bar padding, across the door opening, down the roll bar (I have a 2 door), under the carpet (when I had carpet), and out the tailgate. It's fine.