Seeking upgade advise

I'm seeking advise on what would be best to do.I am wanting to upgrade speakers and was thinking of either changing front and rear door speakers and adding a alpine 445u or just changing the front door speakers out to conponent 6x9 and bridging the alpine to run them. I was just going to leave stock rear door speakers on factory unit.

 

Swap the alpine for the Kicker Key.
Go ahead and spend the extra money to do components up front and swap the rears as well.
They Kicker Key can be bridged for components, but no need to. 90w of power per speaker is insanely loud, and only usable in a jeep with the top down and doors off (from experience)
Use the amp to run all 4 doors at 45w each. Will change your life.