if your going for a true SQ system, dont put any speakers in the rear doors.
high quality ( rainbow etc) components up front running off their own 2 channel amp and a good quality sub in the boot running on its own mono amp.
adding comp's in the rear doors will likely muddy the sound and ruin the soundstage.
however, if your aiming for a loud,clear system thats not going to be entered in comps, then just follow what was said above, move the mids lower down and keep the tweeters nice and high. just dont aim them so as the freq will hit each other directly, ie dont point them at each other.