Can i just run speed wire from my amp to my aftermarket hu can the stock wiringd handle it 75rmsx4

 

I assume you are putting in an after market HU and amplifier, if that is correct then you really should be upgrading the speakers as well, the stock ones won't last long on a true 75x4 RMS amp. Additionally, if you are doing all I have stated here I would run new wiring, I have detailed instructions on a GE in my install log on what it takes for the front doors. It isn't that complicated, and it will be overall better for you.

If you are simply putting an aftermarket h/u in and using the amp built into it, then the stock wiring will be fine. No aftermarket head unit I know of alone can do that kind of power RMS. 20x4 maybe but not 75x4.

 

is this a 75 watt rms amp? or 75 watt rms per channel?
1. f your running 75 watts rms to each speaker u will surely need to run new wires from the amp to the speakers
2. if you are running 75 watts total.... thats like 18 watts rms and is what u would be putting to your speakers from your head unit and youll be ok.

i assume your gonna fall under number 1... and will need to run new wires.
if your under number 2...makes me wonder why youd even bother with such a small amp.