I posted before w/questions about where to drill/mount my amp and I got it figured out, thanks to you guys. I've run into one more issue I'm not sure about though...

I am wiring an 55Wrmsx4 4-channel amp to power my front door and rear deck speakers in a 1997 accord. My original plan was to splice the wires at the wiring harness behind my headunit but I feel like I am going to run into problems there matching 16 and 22 gauge wire, plus, I feel like that's a lot of wire to stuff behind the headunit. Also, I have heard different stories about whether or not replacing factory wire makes a big difference. Which leads me to my big question:

Would it be a better idea to cut and tape off the factory wire to the rear speakers and just wire them directly from the amp? This seems like the way to go for me but then I've got that factory wire just hanging around in the car, still plugged into my headunit.

Then, for the front speakers, is it better to do the same thing and then run the wire from inside the door to the amp in the trunk? I'm just wondering if this is worth all of the work (and door-taking-apart ) to replace the factory speaker wire rather than just splicing into my HU harness.

I'd like to hear your opinions and suggestions on this...thanks