Red Mnster Z

I have a Glowshift wideband AFR gauge that I'm trying to install into my 4th gen Camaro LS1 and having kind of a hard time getting the gauge all hooked up and running. I'm stuck trying to find a hole that I can use to run the extension wire from the sensor to inside my car, or drill a hole to run the wire through. My problem is that one of the connector ends is flat that connects to my little box, and no matter what hole I drill or find one in my firewall, the connector won't fit through the hole. I was wondering if anyone has had the experience of installing a Glowshift wideband AFR gauge in their 4th gen Camaro LS1, and where did you route the wire through?