For my Autocom unit, I put it under the seat (hardwired from the battery) and ran the leads under a handy gap between the seat and frame rail, roughly between rider and pillion. I found that the lead to my headset was a perfect length to run under my left arm, up the front of my shoulder to the helmet. This worked well because the wind would pin the cord to my shoulder and it wouldn't flap around. When we weren't using the intercom, the leads would just all coil up and squeeze in under the seat. It was actually a pretty clean setup, and no tankbag required.