Regarding noise on sub wires. It can easily be a problem if the coax is run in contact with AC wire for any length more than a couple feet. Make sure the sub wiring is not run right along with the electric. A few feet above or below is enough, just not through the same holes in the studs.

Pioneer PDP-5020FD, Marantz SR6011
Axiom M5HP, VP160HP, QS8
Sony PS4, surround backs
-Chris