I used to run "Fancy" radios with WX recieve and the works, but I gave that up for space. Currently, I use a Uniden 520 (Pro520) in both Jeeps and they have served me well for years. I had mine attached to the pass side of the transmission tunnel, but
it got moved when I re-did the interior and now resides where the FM radio was ( I made a bracket for my 98' )
There are threads galore here on CB radios and installations, with pictures, so I won't bother you with what is in the installation/owners manual.
Things I have found to work for me:
Decide on radio location that is easy to run cable to.
Decide where you are going to pull power from. For CB installs, I just go to the "Radio" fuse on the fuse block and Ground.
Mount radio and get power to it.
Now for the tough part, antennas. Ranger Rick advised a roof top install, and that is the optimal place, but frankly it's a PITA for a City Dweller like me who has a lifted Jeep and wants to do City Ramps and park in my garage without getting out and disconnecting the antenna from the mount each time. For my install, optimal was not going to be part of the result, but I didn't want it to perform too badly either.
So for my install, I mounted the antenna on the opposite fender from the FM radio antenna and used a NMO mounting bracket that is right angle, which is screwed to the inside of the fender lip inside the hood area. I also Off-Road in thick wooded areas, so I run a bottom loaded whip (Larsen), which clears the Parking Ramps, and the roof of my garage, and is flexable enough to get caught on trees and still come out alive.
K40 makes a real nice antenna. When I used to do installs, those were the nicest tuning antenna on the market. Barjan (Truckstop branded goods, they own Wilson) makes a base load antenna which is adjusted with a screw on the bottom that I have on the YJ and I like it. Here is a pix of my rig, you can see the Larsen baseload on the left side.
www.mcjag.org/trips/Archive/0606_AVF/DSCF2474.jpg
Ron