Hey! I am new to this community. I have a 2006 GMC envoy and am looking to upgrade my speaker system. I have been looking into speakers and I do not know what to purchase! I have 2 tweaters in the front dash on both sides. I have 2 in the front doors and 2 in the back. To my knowledge the 2 front only produce bass. What kinds of speakers should i get for each location. I am buying an aftermarket pioneer radio, should I also buy a new amp? Or if I sound lost please help me out!