You will have to get a Reciever that supports the size cd changer you have (10 disk, right) so look for one that accepts a 10disk cd changer. Replacing the door speakers will newer speakers is also a good idea, the rear are usually 6x9s and the fronts are 4" you might wanna check up on that, go to
http://www.crutchfield.com and "select you vehical" and it will tell you the size speakers you have, it will also tell you which Reciever will fit. I dont suggust buying from Crutchfield since they have high prices, but use it to find out what fits. You could a sound denting material, such as home instualtion, or other, but dynamot is overpriced. Check out
http://www.sounddomain.com some times they give away stuff like that for amps, speakers, etc.