Hi, i own a 2000 Lexus es 300 and i wanna know what i should do to upgrade the sound system. I already have a aftermarket subwoofer in my trunk. I wanna know if i should change out the speakers, get a new deck receiver or wutever u call them, or should i add an amp to the already factory amp i heard lexus puts in there vehicles somewhere hidden near the trunk. My mom had an old ford van witha crappy sound system and my dad bought her a new deck and it sounded alot better and when she sold that van we had the deck taken out so i can put that deck in for free. Then do speakers? This is what i wanna your opinions on, what should i do?