I think, if you can get it, you will be happy with 0w30 502/507 (I think) Castrol edge titanium. I go with that to stick with the same oil, but the titanium 5w30 LL is a lot more easy to come by here so I am running that more often than not.
The key is oil sample tests, to have this question answered. Otherwise, we will to wait for, God forbid, engine failures.
I can tell you this much though: this side of the pond Castrol (BP) is common in general. The only other oil you, although only rarely, get from Audi here is Mobil1. Most people here don’t know how to change their own oil and go to audi for the 600 USD oil change every 2 years or 20.000 miles.
Here is the point: I have rarely heard of engine failures here in Europe of the b8(.5) rs4 and RS5s. The same applies to the R8 with the same intervals. Based on that I would say that the titanium oil is doing a good job. Once I get a country where people take more notice of oil changes I will have the samples taken between oil changes, even.