need speaker selection

I believe that truck has 5x7" speakers in the doors factory. In the past I have taken advantage of the extra space and fabricated little enclosures for 6.5" speakers out of fiberglass and mounted tweeters on the door panel itself. It sounded very very good, keep in mind that kind of install isn't cheap. You may want to opt for getting plates mounted to fill the hole of the 5x7" speaker and mount a 6.5" mid in there and a tweeter on the door. No one will be able to recommend which speakers will be best for you so stop by your local car audio shops and listen to the component systems. You most likely will need to run the component speakers off of a small amp to get them sounding right, the amp in the cd player just wont cut it. Now for the sub's, check out an amazing sub made by Sound Splinter Audio at www.soundsplinter.com it is the RL-i8 model.2003 Chevy Avalanche,Eclipse CD7000,Morel Elate 5,Adire Extremis,Alpine PDX-4.150, 15" TC-3000, 2 Alpine PDX-1.1000, 470Amp HO Alt.

I believe that the speakers are 6x8's all the way around.

Thanks for the suggestions. I have such a difficult time knowing what to do for a set up.  I see I will have to have an amp to power the system. I guess I will go with some component speakers with a small sub.  Once again, thanks!Grey1998

2nd vote for the soundsplinter rli-8".  Heard nothing but good things and Mike @ soundsplinter is a great guy to work with.  Check out this link to see them in action: http://www.teamtoxicbass.com/~pete/car_audio/project_hellboy/index.html