Dr. Bogger wrote:...Currently in my car i have 6x9's in the back, and 4x6's in the front, but i am planning on changing that in the near future.
You say you are "planning" - before you put a plan together, read this first:
http://www.betteraudio.com/geolemon/phasing/phasing.htm
You might just reconsider having any speakers in the rear at all.

(nice side benefits too - more money to spend on good speakers, more bass in car, fewer rattles, less distortion

)
How many high-end home stereo systems do you see with more than two speakers? You got it - zero.

Music is recorded in two channel stereo - you can only play it back in two channel stereo - and as soon as you introduce multiple sets of speakers all playing the same thing from different distances from your ears, phasing anomolies start to wreak havoc with your imaging and SQ.
Anyway - check out the link.
