I am looking to upgrade my sound system in my car. I have the 17 Fusion Sport with 12 speakers. I would like to upgrade my 6x9's in the deck. Just want more good quality sounding bass that puts out more bass. Not sure where to turn to. I saw the JBL GTO939 but I'm not sure. I'm willing to spend $600 on speakers. If I replace the 6x9 in the deck, and I can just put the tweeters in the rear doors. I would also like to possibly replace the front speakers in the doors but I want it to match the sound in the back.. I can up my price if needed.. And if someone could help, the stock amps... I heard that there is two amps in the 17 fusion sport with 12 speakers but I can't really find much info on it. I would like to know information about the amp.