Just finished testing the signal amplitude mode, so far, so good. It varies the output amplitude from around 1.1:1 to 3:1 from stop to stop. Most folks won't need this, however if you're running LCS Sensor Tracks, or you have experienced DCS issues after adding the TMCC Buffer, this mod may be the ticket to the two systems coexisting.
The installation is fairly simple, see pictures and description below.
Remove R5 and solder pot and resistor combination across the R5 connection
Close-up detail of pot and resistor assembly
Drill hole(s) for amplitude adjustment pot
Mount pot and reassemble case
That's the installation process, so it's fairly simple to upgrade the box.