ok. you do not want to put 4 sets of speakers in your car. go for quiality not quanity. yes putting 4 6x9'* and a pair of 6.5'* in the rear doors will get you volume but at what cost. you would be way better off getting a good set of 6x9'* and a good set of front speakers. i run jl audio and trust me you can hear them VERY well. to the point that your ears will hurt if you push it. good speakers and a good amp is way better then a crappy amp and 10 speakers. if you just spend the money right you will end up with a far superior set up. not to mention with 6 speakers in the back of you car it will sound backwards. you need most of you sound coming from your front speakers for a good sound. i run 6.5'* up front with 150 watts each and 6x9'* in the back with 75 watts each. even with that to get the sound right i had to cut the signal going to the 6x9'*. sounds to me like you need to stop using the power from your cd player and get a amp. that is why your subs sounded so much louder then your highs and mids.
20" Jessie James type .44'*