I'm using Motul 300v 5w-30 with apparently (no used oil analysis done by me) very good results. Car idles like clock with no hiccups, engine noise is reduced, overall the engine runs very nice. The downside is that you have to change it every 5000 miles, although I have seen oil analysis showing that it still had a good amount of additives (TBN) left after 5000 miles (even more than other normal oils).
The advantages of the 300v are its double ester base which is the best oil base available today, which means it provides top notch lubrication, it sticks to the metal surfaces even if car has not been used for a long time, and that it has a high HTHS value - this means that it maintains viscosity in extreme temperatures (150 Celsius) - good for the turbo environment.
I can definitely feel an overall improvement with this oil over the previous Castrol Edge 5w-30.