2000 Silverado speakers

I'm a little confused concerning my 2000 Silverado stereo. (Z-71, ext. cab, 3 door, type LT)

The first thing I find interesting is that all references I've seen about the rear speakers location, (including this site) say "rear pillars". They're in the doors.That's no big deal, although I would have used larger rears in my sound system upgrade had I known how much room there is in the doors. 

The main question I have is... There is no reference anywhere to the fact that the front speakers are components, and have two seperate harnesses per door. Are these in parallel somewhere between the deck and the door?

I'm not sure how to wire my Infinity components. (with passive crossovers)

Any help is appreciated!