When replacing the rear speakers in a Grand Am, measurements should be taken to get the exact dimensions first. It is best to remove the speakers and take them with you to match them up with the replacement speakers. The reason for this is that the rear speakers are mounted under the rear package tray. When the car was built, studs were installed in the rear deck. Speakers are installed on these studs and nuts to hold them up. Some model years may use screws. In any event, it is difficult--at best--to get at the speakers and if they do not fit it would be difficult to make them fit.
To get to the rear speakers, you must get into the trunk and on your back to get under the speakers. It might be a good idea to get speakers that are top mounted or a set of enclosed speakers. These are in a box or a cylindrical tube. They provide superior sound and are easier to hook up as opposed to the stock style speaker. Top-mount speakers come in a housing and need only to be screwed into the topside rear deck. The tube of box speakers just sets in the trunk toward the back.
The speakers, regardless of style, need to have a minimum of 35-watt capability and a maximum of 100 watts for a stock system. If a box or tube is more desirable, keep the power ratings in mind and also get a small box with dual range speakers. This means speakers that have dual cones for bass and mid range. Full sub woofers demand more power and will not have any mid range and would reduce the sound quality.
To remove rear speakers, remove the wires attached to the speakers. Remove the four nuts and work the speaker down off the studs. Install the new replacement speakers the reverse way they came off. For the box speakers, put them in the trunk and lengthen the stock wires to reach.
