I do headrests on a frequent basis. Depending on whether you go with prefabbed or not will determine how you run the wires by the pole. If you do go with prefab, most of the time the wires go thru the pole. If you cut your own in, then you will have to run them along pole, tucked underneath the plastic insert thru the seat. I usually find a channel where the back rest pivots so the wire doesn't get pinched. If you have a center console all the way up to the dash, then you have an easier time running the wires up to the radio or brain. If you don't, then try to run the wires thru a factory cut in the carpet underneath the seat. Pop off the floor paneling and run up to the radio that way. It's not too difficult. Almost all the paneling is just clips and pops out.
Hope this helps a little.