I ran a set up just like that on my last AV and i was really not happy with the output of just running it from a cobra cb to a radio shack PA speaker. Yeah it will work but it will be very soft compared to Police models. If you really want to be heard get the cb get atleast a 100watt PA speakers ( this is something that you just dont cheap out on since it will be in harms way of the elements) it will run you any where from 40 to 80 bucks depending on the brand and size maybe more . Install the CB where ya want and run the wire from the cb output for the PA to the Amp to the PA speaker . I placed mine inside the front bumper and it took some abuse so i would take Trident's advise and place it inside the engine compartment . Also instead of running the wire through the fire wall there are 2 drain plugs under the carpeting on the driver and passenger flooring right dead center almost where you can run the wire alittle more easily than the fire wall install. While you are there also run your CB ANT. wire for future install and it will save time , just tie up the wire good with Zip ties and watch out for moving parts. well that was my exp talkin , keep on keeping on man !Here is a pic where i installed it. I just got done tonight with it and it took me about 2 hours to figure it out but if ya know what you are doing and how it should only talk about an hour honestly. L8