So the only speakers in my truck will be some components in the doors/a pillars.... or near the pillars for the tweeters, and a subwoofer i shouldnt do components right behind the seats in factory location

 

If it's sound quality you want, then you want to recreate the image of being at a concert. You don't want speakers behind you as it will pull the stage behind you. Some like that kind of sound however. As a general gauge, sit in your vehicle and look straight forward. Place speakers anywhere within your vision, including peripheral vision. I've been playing with speaker location to try and find what I like before cutting anything or going to the extra effort to fibreglass something in.

One 12" sub in a sealed box, space permitting, will be plenty for what you are looking for. I had a JL 12W3V3 in a sealed box on 150 watts and it sounded pretty darn good. Still had to turn the sub gain down a little to get a nice blend of highs/mids and lows.

 

i run 2 6 1/2 alpine's in the front (150watss rms) each, and i run a 12' W0V2 JL sub in a sealed box SQ is amazing its all being powered by a alpine V12 mrv- somthing the sub runs a lil underpowered but it works great