I had to go download and read the manual for the MMG-C to understand what they were talking about. Even after reading it, I find it to be a curious wiring arrangement. It would appear to apply solely to the case of using an MMG-C with MMG fronts. Are you using MMG fronts? If so, where are you crossing them over? I'd lean toward 80Hz for the MMG's and 100Hz for the MMG-C (the latter being Magnepan's recommendation as well). In that case, I'd have a hard time justifying the extra wiring for myself, but that's just me...