Hi guys , Im looking to upgrade the sound system in my C class 240 benz for the fronts I already have from my previous car a set of jbl's 6.5 inch 2 way coaxials . Im gonna buy some autolead speaker adapters to connect my jbl's in the front. what can I put in the rear shelf for bass fill ??? I dont know what size the speakers are ....im guessing 6.5 inch but im not sure , Im not even sure 6.5inch speakers would do the trick ! what can I also put in the rear doors ....are these 5.25 or something ??? I think I need to take off the whole door panel to replace these babys ....sounds like too much hard work! Ideally I would like an amp and sub but I dont want to start cutting holes where I shouldnt ..so for now I just want it to sound good at high levels with enough bass fill Any suggestions guys ???