I just got 4 new speakers to replace the stock ones (IN my '84 GS), and I noticed the sound is very muffled my the time it reaches me
Where are some good aftermarket locations to mount the speakers?
Front can go on the door, but what about the back?

 

First off what kinda speaker are you upgrading to? Secondly did you check your deck? Factory or aftermarket? If you have a factory bose then you might want to remove the amp and power the speakers with an aftermarket amp. Should be better