After i bought all the bits you listed the seats wouldn't heat up and found out you also need an upgraded control module approx £100 ebay
which allows heated seats and also fitting of LED headlights if required ,the module is located under the the steering wheel to the right.
What I would do if I was you is ring Audi with your reg and they will tell you the part number for your car, I made the mistake of ringing them after I found out I'd bought the wrong one, but at least I know now.
It could be that part number or 8J2837015C , if it is the part ending with a "C" i have a brand new one for sale. You can check by phoning Audi and giving your car reg, they will tell you the correct part number.
I have done this mod on my car, what you do is use the loom from the A4 airbag and not the TT loom ,when you change them over you will notice the TT loom has different spade connectors which are the earth for the horn and there are 2 on the TT loom and only one on the A4 loom.
I cut the spades...