@tonymcross - There should be no differences if using 3.5mm TRS or TRRS, and this is because the whole point of having S-Balanced in the first place was to get a Balanced performance in Single Ended mode. I actually do not have the cables necesary to test, but ifi themselves write in their papers that the whole point of this connection was to never "need" balanced cables for their DAC/AMPs
Headphone Reviews and Discussion - Head-Fi.org
I'm curious about the SQ difference between 3.5 and 3.5 TRRS, if you've got necessary equipment, of course.