how many watts can your stock h/u support? are you also planning to buy amps if the H/U lacks juice to support the new speakers?
I went crazy once with a sound system in a car. Now I just upgrade the stock speakers on the factory unit and add a self powered subwoofer. The electronics store if not Crutchfield can give you a good idea as to what speakers will sound good with the oem head unit.Very clear and good sound and more bass than you should subject your ears to.
Oh dynamat the car it not only improves sound but will help keep your car cool.
Guess it all depends on what and how you want to hear it
I can't stand sitting a guys car and have him crank up his system hearing his body panels, trunk and door rattling, and turns and looks at me and ask me "How does it sound?" I tell him sounds like crap. I like a bass and I like it loud but if it isn't clear it's crap
What ever you do don't toss your head unit it cost and arm and a leg and some features options are sometimes in the radio
are you a member of any Avalanche forums? might be a good idea to take a peek and see what owners have to say. meanwhile, see what Crutchfield will recommend: Car Selector
i am I searched there but could not find it I will post up and try and find out
Kicker are great but costly and the Polk suck. If you are keeping the stock head unit look into Eclipse, they make great stuff for good cost. You should be able to pick up a pair for right about $100.00 and they have the cross over and seperate tweeters.
do the polks and do your own install save your money if the tweeters aren't blown and are working leave them as well avalanche wiring colors are gray/tan gray is - tan is +
for drivers door and pass door is light green and dark green, light green is + dark green is - its the same for all gm vechiles to 2008 back to early eighties