I left the usb side of the adapter alone as you can see in this pic.
I only tapped into the side of the headset 2.5mm jack.
I left the usb jack on the adapter so i could still charge my phone with the usb. As i have a power inverter in my car with a long usb cable to the inverter to use as the charger bc it has usb output on it, and my usb car chager has a 90 deg andgle on it and a coiled cord so it looked like crap hanging off the adapter.
I still need to clean up the wiring a little to make them neater but it works and i will get to that later.