Speakers to replace????

[pike110]

I have a set of polk 6 1/2 comp. sr6500's. I was going to run these with a kicker kx550.2 amp. I am putting them in a 2000 s-10 extended cab. The factor speakers are 4x6's on the dash, 6 1/2 doors, and 6 1/2 in the rear from factory. I am going for sq. How would I go about doing this? I am already replacing the door 6.5's with the polks, but should I replace the 4x6 with another set of polks and run them on an amp also? And what should I do with the 6.5's in the rearfill? Please help!!

[pike110]

Anybody have any advise for me?