After you have lead the power wire to the seat area there should be 4 grounds. One for each switch and one for each seat:
Out of the very few wires I crimped (only wires such as this were crimped) I soldered the connection and then shrink wrapped the rest:
Eventually lead your wires up to the center console area and you have then have properly "factory equipped" heated seats:
I have to say right now I'm enjoying the heated seats the most. I highly recommend anyone who has WRX seats that doesn't have the heated part hooked up to do it.
Rigged up some cheapo JBL speakers for the front doors (the speakers were $25 from Best Buy on clearance brand new).
They fit perfectly with the OEM mounting plate thing.