I run alot of IT and communication wires and let me tell you that a twisted pair wire helps geatly with reducing noise. There are a few system that will not work if the wires are not twisted b/c of the excesss noise.
I wonder if you put a sheilded tube over you high current wires if that would help to? I bet raping your wire would help keep it clean.
I ran the old Spektrum (in an M8) & am running the DX3R now and do not have range or glitching issues. (As long as the BEC is good. If you have a dodgy bec that does not put out clean DC, you could have glitches. that's what Spektrum sells the cap for.)