Damn my dogs would be smitten as kittens with heated rear seats. For the love of god I hope my wife does not find her way to this thread or I will be ordered to have this done ASAP.
I installed heated front seats in my wife’s 2008 Expedition years ago. It was a bitch taking out the seats, undoing the covers (seat and back), installing, hog rings up the $&?@#%, and wiring and reinstalling them. Plastic trim clips breaking off, a new $135 seat side panel later, I’d never do them again. Until next time
I plan on doing this mod eventually, for $73 though. I did it to my Forester STI-clone a couple months ago. I used an unused 15A fuse which is ample. I believe when both sides (4 pads) are on high, it only uses up to 74W. It looks just like what the OP showed. The labor is a bit tricky I'm sure. I still have a bunch of the hog wires and the pliers, so I might as well. My daughter and her friend will sit back there from time to time, but she's driving now so probably not that often.