After puting the EMS unit back in the cubby and closing it up, I could not hear that hum as before. I asked my DW and she could only hear the hum if she was within 3' of the lower cubby area.
Overall, if you are comfortable with splicing wire, following the written directions and know where your TT's Power Cord Junction box is located, I would say this Mod is pretty easy and not a required dealer install. Just make certain to disconnect your battery and shore power.
Progressive Industries has 24/7 voice mail monitoring support. Their tech called me back on a Sunday about 45 min after I had left a message on their Support Line. PrimeTime's Support responded to my support email request on a Saturday (Thanks Shane I. & RV Guy!) regarding my initial question and a follow up one. So again great products, great people!!!
2003 Maxima GLE
2010 370z Convertible 6 Stick
2011 Expedition 5.4L 4x4 Limited
2012 Tracer 3150BHD Touring Edition