I fought with Borgeson about my box as well for the hissing. I went back and forth they blamed Bergman's coupler for the noise as their coupler has some rubber/RTV in it that they claim solves this. Obviously Bergman autocraft called this B.S when I showed him the response I got.

In the end Bergman got Borgeson to take the box back for warranty. They "repaired" it but didn't detail as to what. I haven't been out with the car yet but from driveway tests it seems to be solved so far.