I have done it.
I went from m-sport to sport heated. I refused my DCT paddles that work differently than auto and I reused my m-sport trim with buttons.
Then I bought lower trim cover with heated button.
Then I bought clockspring with switches as this is how they usually sell it on ebay. You can recognize heated clockspring by looking for blue connector. But don't replace the switches midule. They contains SZL module that will require coding and calibration if you do that.
I replaced my +-1mph cruise control stalk with +-1 and 5mph though. In the and I didn't get +-5mph feature as I think it requires 544 option coding which I may perform in the
future.
I have not buy any connectors except for Fuse tap. I had some tiny computer connector, to which I soldered two 18awg wires.
I stole wires from my office.
I didn't know which part number is the 12pin heated clockspring connector, so I ghetto it by shaving of a plastic table from existing 6pin plug and sticking it in along with 3 pin connector from the heated switch (after soldiering its ground to my main ground wire) and along my tiny (black) computer connector next to it.
So in total I fitted 3 connectors in this heated 12 pin socket with a drop of hot glue to secure it. Ghetto, but it works. Tiny connector doesn't overheat and it doesn't add much resistance as it is not long distance.
+12 you can get from fuse box. I though I could do it properly by basically adding anither fuse there and connecting on the back of fuse box (junction box), but good luck with removing the fuse box.. I ended up doing what everyone does which is tapping into a fuse slot. I used #5 slot. But it doesn't matter. There is many that are ignition triggered. I also tried accessory slots and it work all the time, but in the end ignition one is also good (it is active after one press of start button, engine doesn't have to run).
It's good to remove climate control trim to route the cable. Don't brake the plastic panel trim. It's fragile. Just don't brake it.
I found relatively good ground next to driver left leg. You have to remove the lowet cover where legs go and there will be one screw holding upper knee panel to steel frame. I shaved a bit of paint from the screw for better contact and added ground tab there.