I don't think you will have any problem getting this done. I just purchased a high-pixel cluster to replace my existing low-pixel cluster (which replaced my OEM no-pixel cluster), and I am going to get my dealer to install this new, fancy cluster when I take the car in to have them set up the levelling on my OEM Xenons later this week.
My dealer (in Canada) had no problems at all putting in my low-pixel cluster, so I don't think they will have any problems putting in the high-pixel one. The dealers have a fancy VAG tool with a LCD display screen on it (VAG-1551?) - this pretty much prompts them through the whole process. Just be sure to take all three car keys with you when you get the cluster changed, they need all the car keys to do some kind of adaptation to the anti-theft system.
When they did the installation of my low-pixel cluster, it took them about 45 minutes to figure out what to do, then about 10 minutes to do it. Just one suggestion: Be nice to the dealer - take them the part in the sealed box, don't screw it up first trying to program it yourself, then bring a mess to them and ask them to try and sort it out (not that I am suggesting you would ever do that).
Below is a picture of the part number for the high-pixel cluster:
Part Number for High Pixel Cluster, metric measurement, chrome rings, TDI tachometer