Looking into upgrading my TJ speakers

I should really stay out of this one. But, I will interject one statement from Wikipedia regarding quadraphonic sound systems.

"Reproduction in the rear speakers should be of the same quality or almost the same quality as the front speakers. Ideally, it is preferred to use four identical speakers." The reasoning is obvious, at least to me. Look at Bose systems. They are tiny speakers providing some of the best sound. Size really doesn't matter. What is most important is the sound balance so all speakers reach your ears equally, with the same sound quality, preferably with four identical speakers.

fade to the front speakers a bit and front vs rear sounds the same. this would need to be done even with the same size speakers all the way around as the rear speakers are so close to your ears. that is if you desire to be able to hear the front speakers.
 
fade to the front speakers a bit and front vs rear sounds the same. this would need to be done even with the same size speakers all the way around as the rear speakers are so close to your ears. that is if you desire to be able to hear the front speakers.

There is a better way. First of all, fading the speakers actually imbalances them. You squelch the natural sound balance coming from the speakers. In the studio, they don't fade the speakers and some studio recordings were actually done with quadrophonic sound. Plus, if you have fade out the bigger sounding speakers, then what's the point of having larger speakers? Now, if you have four speakers all the same, you can polyfill the rear of the front speakers until they sound the same as the rear speakers. You are just pushing the sound further, while not changing the sound quality. It really doesn't take that much polyfill. Then, you have zero fade, hearing all four speakers naturally, equally and optimumly. I actually packed my front speakers with so much polyfill that I had to take some out until they sounded perfectly balanced with my rear speakers. I guess I could have packed a little in my rear speakers to reduce sound loss and then pack more in my front speakers to balance them out. But, I'm just not that much of a perfectionist. As long as the speakers reach my ears equally, I'm good.