Help with stereo upgrade

[9864ever]

I though wiring the door and dash speakers to the deck might be easy but it sure isn't These wires run through the firewall to the amplifier. I thought about tapping into the wires somewhere from the cabin but it looks like they are wrapped tightly in a 1" loom with tons of other wires so that's not going to be easy. Looks like I have to run new wires unless someone has any ideas?

[9864ever]

I did a workaround in case anyone wants to know. I soldered new wires onto the existing 4 speaker wires in the frunk where the amp was. I then ran those through the firewall and connected to the head unit. This was the easiest solution and worked quite well.