For 06-07 are the rear deck speakers mainly lows? ESP in the ss models? And is it the same for 00-05? Mids seem to be the tweeters, door speaks are the highs and I'm assuming rear are lows, at least from my ears

 

Your are correct. The rear speakers are more like low/mid and the doors are like mid/high.

 

So the 6x9's in the back should be replaceable with 8'' subs and work fine. Aha great. Maybe ill add a componet system to the doors for some extra mids and then subdue them in the back with subwoofers in the deck. Awsome.