It's all about antenna, antenna location, and tuning.
basically all CB's are 4watt TX power, antenna is everything, you Must tune the antenna after final instalation with an SWR meter. If you dont your setup can work VERY poorly, and can burn up your radio instantly or eventually.
look for a 5/8 wavelength top loaded antenna. Taller is Better.
stay away from base loaded and glass mount antennas.
Counterpoise (ground plane) Must be considered, this is extremely important.
If your antenna follows metal (windshield frame, etc...) and is not sticking up at least 2/3 of the way it wont work worth crap.
Ideally you want to place your antenna on the middle of your roof, for an excellent ground plane, but thats rarely feasable. Sometimes you'll see the rednecks in there huge trucks with cophased antennas on the front bumper, this helps use the grounded metal in between them as counterpoise.
if your vehicle is non ferrous (plastic, fiberglass, aluminum, cheese, etc.) use a no ground plane antenna
use correct antenna wire for your setup, 18 feet is ideal.
higher quality parts are better, go to a truck stop, not radioshack
being very space limited on my wangler I went with mounting it here, still need to tune it.