Also, i know the door panel only fits 4 inch speakers? or is it 4.5 inch? besides that is there some way i can fit bigger speakers in there? i remember reading something on this site that someone adjusted it to fit in 6.5 i think but i cant find it. But with all of your experiences does the 4 inch really do the job? I'm thinking of going all pioneer, i found some nice 5 way 6x9 speakers but how does kenwood compare to them? thanks for the help guys!

Not sure about the other questions but someone will chime in.

I just wired the new head unit with the old wiring, which allows you to run the rear speakers off the stock amp. as for the fronts, I have the 4.25 pioneer speakers and they work very well. i have infinity 6x9 in the back wired directly to the stock amp. it is pretty straight forward it just takes a few hours to get it all set up.

Sorry if I am being to vague, if you have any specific questions I will try to help you out.