get yourself onto talkaudio forum and have a read at why 6x9's are pointless as are any other rear speakers.
Im not going to go into it too much, but they ruin the sound stage. When watching the tv are the speakers on the tv or are all the voices coming from behind you?
If unsure, try it looking in a mirror at the tv and see what sounds best
Also you mentioned 6x9's with a boot install, they will have being doing nothing, when a 6x9 uses the same airspace as the subs ie boot then the pressure created byy the subs makes the 6x9's move, meaning that the midbass which they are intended for wont be being produced properly anyway which is why an amped set of components in the front doors with plenty of deadening is a better option with a sub in the boot.