Tested the new setup today by calling my mom on the drive. According to her, "it's better, but still not great." She had difficulty understanding me at points and I ended up finishing the phone call using the phone itself. I'm not pleased with this; I think a directional mic replacement is the only real solution. I'm going to play with the existing mic / wiring to check the pinout of those wires and look into a replacement. It may be up to a week or two before I complete this part of testing, but I'll post up after I do.