Robert
It's pretty easy to fit one to the D2. However, the picture of the one you linked to is different from the one I fitted to mine recently. Mine looks more like this one:
http://www.ebay.co.uk/itm/Audi-A8-19...QAAOSwbYZXYYJ7
I'd normally try and take photos of jobs I do, so I can write them up for anyone else thinking of doing the same thing, but never did it for this. From memory, what's involved is as follows:
1. Unclip rear wheel arch liners from bumper
2. Unclip large piece of plastic underneath right side of car
3. Remove two large bolts securing bumper to bumper pistons
4. Pull bumper backwards 2-3 inches. Whacking it with your hand from the bumper ends helps get it moving
5. While still resting on side clips, detach cable for reversing sensors at the left side, underneath the lights
6. Pull bumper off completely
7. If you have the threaded section for the tow hook on the right hand side, this needs to be removed. There will be three bolts holding this in position
8. You will need to remove the bumper piston(s) in order to insert one of the bolts. If you're lucky with part 7 above, the bolt may be seized in placed and you won't have to remove the piston
8A. You also need to drop the rear of the exhaust down, as well as the heat shielding to get at the bolt holes. I just took it off the rear rubber exhaust mounts and had a few blocks in place to support it
9. The hardest part is next and that is getting the towbar held in place, whilst securing it in place. There will be six bolts in total
10. Assuming you have the 13 pin plug in place, you now have to get the wiring inside the car. If you're patient enough, you can feed the cables through the large grommet the reversing sensor wires come through
11. To wire it up inside the car, there is an earth point down below the light cluster, near the outer corner of the car (between the outer skin and inner boot lining). You may need a torch to see exactly where
12. Luckily, the rear lights have additional spade connectors on them, which allows attachment of the towbar loom. Again, from memory, I connected two on the left and three on the right. I didn't wire up the reverse light (since it's in the bootlid). As to the towbar loom itself, I just ran it across the back of the boot (nearest the bumper, that is) underneath the floor mat
After that, and you've tested everything is working, it's time to put it all back together again in reverse, so heat shield, exhaust, bumper piston(s), bumper halfway, reversing sensor wire, bumper full way and bolted, wheel arch liners in place and secured with clips. Finally, you may have to cut a section of the large plastic liner (2 above), to get it to fit around towbar.
Hope this gives you some idea of how it's done, and I hope it doesn't take you as long. I bought mine from The_Laird in June 2015 and it took to May 2016 to fit it, and another 10 weeks to wire it
