Use a harness adapter. Connect only the power and ground wires to the HU. The speaker wires from the HU need to be left disconnected and taped up so they can't short to each other or to ground. The front speaker wires from the harness adapter splice to the new speaker wires that go to your amp. This gets the front speakers working without needing to fish new wires into the doors.

The rear speakers should be hooked up directly using new speaker wires right from the amp to the speakers. Leave the stock harness disconnected.

 

This "should" be correct for your vehicle:

onstant 12V+ Blue/White
Switched 12V+ Yellow/Red
Ground Black
Illumination Red/Black
Dimmer n/a
Antenna Driver's Pillar
Front Speakers 6 1/2" Doors
Left Front (+) Blue
Left Front (-) Gray/Black
Right Front (+) Red/Green
Right Front (-) Brown/Black
Rear Speakers 6" x 9" Rear Deck
Left Rear (+) Blue/Yellow
Left Rear (-) Gray/White
Right Rear (+) Red/Yellow
Right Rear (-) Brown/White

I recommend testing with a AA battery on the speaker wires just to be certain. It will give you a minor pop from the speaker as you connect the positive and negative wires to the positive and negative of the AA battery. I'll usually hold the positive down and touch the negative off and on to determine which speaker is making that popping sound.

 

So just unplug the front speakers from the harness and attach to the new wire. Got it. Thanks