the thing for me is making it looks completely oem like the front doors and teh rear hatch speakers, with a narrow door panel you get limited to 4 inch or 5.25 inch. then you gotta make it look stock. imo. i'd hate to have the rear door speakers have a grill on top of the door panel while the fronts have the stock grill.
My rears off disabeled also because of the box. So what I did was get a better front stage. My car is getting the tweeters in the A-Pillars and some mid-range 6.5s in the door. If your front stage is strong you dont need speakers in the back doors.