Diff between RC wire and automotive wire?

[JThiessen]

These are actually for the motor to esc wires, so once its set, I should be good to go. The Tekno conversion kit I have for my 8T puts them so far apart the wires wont reach. I had an extra set that Castle sent me, but even splicing the two together has them tighter than I like. I'd rather get some long enough, and do it right the first time. I wonder if some high end speaker wire would be better.....
I plan on shrink wrapping all three together to make a cleaner routing, also, so that will reduce movement as well.