6 Speaker Upgrade + Amp but No Sub (Input Asked)

[Brock9281]

I replaced the 4" speakers with Hertz speakers and the 6.5's with Memphis Audio woofers with %100 efficiency .... the front 4" and 6.5 inch is powered by and Key 200.4 amp and I am very very happy with the sound stage but I feel i would have gotten even more if I went with 2 way speakers instead of the woofers
the back 4" speakers are just replaced and not amped .... although its and improvement I am not happy with it .... I will be adding an amp to power the back speakers and I am thinking of adding a powered 10" sub to complete the whole sound system.
I am thinking about changing the 6.5 woofers with 2 way speakers but haven't decided yet.

Can you not power the rear also with the Kicker 200.4? Which Hertz did you get upfront and how would you describe sound?

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