Upgrading Sound System on 06 TB

I'm new to the whole sound system scene but I was wondering if any of yall have any opinions or comments on my plan.

I have a 2006 Trailblazer with a stock, non Bose, speaker system. Since tomorrow is Black Friday, I was planning on taking advantage of all the deals. I am planning on upgrading all of the door speakers instead of adding the box to my trunk. I'm mainly looking for sound quality over loudness. My budget is limited to about $500.

For my upgraded dash unit, I am planning on getting this Kenwood KDC-MP342U:
http://www.crutchfield.com/p_113MP342U/Kenwood-KDC-MP342U.html?tp=5684

For my upgraded door speakers, I am planning on getting these JL Audio VR525-CSi speakers:
http://www.crutchfield.com/s_136VR525CS/JL-Audio-VR525-CSi.html?c=3

If I do this, will I also need to buy a new amp to push these to their full power?

Thanks in advance to all of the responses!