I just measured the door speakers in my truck, and up front they measured 5 1/2" x 7 7/8" and in back they measured 5 1/2" x 7 1/2" No, I'm not a retard, I was holding the tape measure straight.
I assume them to both be 6x8s, but I was hoping someone more knowledgable on this could confirm this before I buy and try to put in 6x8s, and maybe explain the size difference.