I do not have humos or using rear speakers, i just installed a killer SQ system. Based off what i found during my reaserch you woul probably need some type of enclosure for the speakers to sound best.
However, with my new set up I have enough power to hear the stero top down with clarity and plnty bass. So my recommendation is change in HU, speakers and decent amp.
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2000 Boxster S Ocean Blue Metalic
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