now, with that install, did you hook it up to use the OEM USB and aux input? or just left it with out the connection?

 

You can use the stock USB/Aux connection. Follow the instructions in this sticky on how it's done:
https://www.scionlife.com/forums/sho...d.php?t=207173

What I did with my AVH-P4300DVD was just stripped the USB cable that came with the deck using the steps in that other thread and connected that to the stock USB/Aux connector. I have no need for the Aux so I left that off.
Also doing it this way will not allow you to play videos from the iPod/iPhone as you must use the specific iPod video cable. You can play music fine though.