Boosters came over here at the same time the original cb did. It was AM back then and the range wasn't great. Many people fitted amps (boosters) to increase the output from a few watts to 10,20,50 or even a few hundred watts. The range increase was pretty good but you have to remember that the increase is not linear.
If you have a 10 watt radio and want to increase the performance by 100% you do not double the wattage... you multiply it by 10. So 100 watt radio is twice as effective as a 10 watt one.
Most of the time these enhancements are not necessary in our motors because we use them primarily for keeping in touch with other motors who are close by...certainly within a mile or two.
When CB became legal the government had a problem. Thousands of us were using the illegal rigs imported from the states and operating on 27 Mhz AM. If they legalised this system then they would lose out on much tax. Instead they commissioned an FM system. Fm has advantages over AM in areas like range and clarity...(just listen to an AM radio station and then return to FM if you don't believe me!
No one worries about burners and boosters any more. The legal limit on your rig is 4 watts. Depending on location and terrain this should give you an effective range of five to ten miles... more if you are high up.
If you need better range get a booster.
The attenuator switch drops the output of the rig. Originally from 4 watts to half a watt. It means that you can be sure that you are not going to interfere with other radio equipment if you are chatting to someone close and do not need the extra power. It will not affect the reception... only the transmission effectiveness.
You need to consider what you want from the rig before you install the antenna. Placing the antenna at therear of the vehicle will ensure that the shape of the wave created pushes most of the signal forward... useful if you are usually at the back of your group. PLacing it at the fron has the opposite effect. The wing or light bar are usually favourite but bear in mind that aluminium does not count as an earth or groundplane and if you mount the antenna on an ali surface then you must also earth the antenna to something big and metalic!
I won't start on about SWR in case you know all about it... but don't be tempted to run the radio without setting up the SWR because an incorrect setting can... and does blow your output transistor leaving you with only the very minimum output power.
Sorry bout the long post but I though it might be of use.
