Hi it was a nightmare removing the cooler the first time a bit like a Heath Robinson jigsaw, two days to get out and a day to get back in with no undue swearing, by time three we had worked out the only real way to do the job with less time was to remove the whole front of the car and disconnect the exhaust and pull the Cat/DPF out of the front so you can get at it, thats what I did first time, cleaned the cooler and got a new valve assembly, guess what that don't work within 30k I had adblue crystals around the exhaust tail pipes where the cooler had corroded and the cooling tubes had collapsed, back to square one, new cooler and managed to salvage the valve, then 60k later replace the lot, YES I would advise steering clear especially as your vehicle has had most of its useful life milage wise why do you think there are so many appearing at what you would consider a bargain price, brain says luxury car dont worry about the milage, Audis are good for milage right, possibly a lot of the others Q3/A3 but not this specimen anything with an ULTRA badge will have the same problem.
Steve.