Hello, I am in the process of replacing all the speakers in my car. The other ones are rotted out. I would prefer not to use 4x10 speakers in the rear again. what is the biggest speaker I can fit in there. Will a 5x7 fit with the right sized magnet? or will I have to do something more like a 4x6? I just dont want to change the appearance of the interior so it needs to fit back there! Also, if I decide to put a sub or 2 would it be a bad idea to put them in the trunk? Thanks David