06 Corolla CE - Front/Rear speakers change out question...

[flexnix]

I got a headunit and I decided I might as well start with changing the rears by myself this weekend. I want to confirm that the size for the rears are 6" x 9"s or 5" x 7"s??

I plan to get a set of Alpine Type S. Any of you installed these in the rears? Will I have to cut any wires and add connectors to them or do the stock wire connectors hook right up?

I guess I would start off by removing the 3 head rests on the rear seat. Then from there I pretty much don't know what to do next. Same thing goes for the front speakers, how do I remove the door panels and what size are they? 6-1/2" or 5-1/4"?