[musicboy]

Rear speakers do degrade the stereo soundstage (except as part of a surround system), but if you like the sound, do what you prefer. I knew a guy who won one of the big national sound-off championships with just a left and right front speaker and a sub. Dynamat will keep the car panels from resonating to the frequencies generated by the speakers, thereby lowering distortion, but it also adds a lot of weight.