I suggest you do upgrade the speakers and add an amplifier when adding the dual subwoofer setup. The main reason being, you can not utilize the full potential of the subwoofers because it will overpower the speakers and all you will hear is bass. To even out the sound, amplification of the speakers is a must. With the single woofer setup, its not as necessary, but soing so will greatly enhance your sound.Do you need to upgrade the speakers when you do the new box. I care more about the quality than the boom
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