front and rear door on same channels?! i don't get it. 
are you setting up the sound for yourself (as the driver) or for people sitting in the back? is this how ur supposed to do it? cuz i was thinking of adding door speakers too...
given the type of music i listen to (mostly psytrance) having rear door speakers on front channel will kinda mess things up. if you can bardaashto-fy that kinda music, have a listen to "heavyweight" by infected mushroom. or "cities of the future" by the same band. the sound travels between speakers/channels and u can feel it moving around u... with your setup i dont think it will be a lot of moving. but of course... since i havent auditioned it yet, i could be very wrong. have a listen to these songs (at at least 75-80dB sound pressure; loud, but not ear-drum bashing loud) ...in a quiet environment and temme how it sounds.
