When I got mine a couple months ago, the service manager told me to order a case of oil. They go through oil. Oil for the turbos comes from the motor. So low oil means no oil to the bearings in the turbo. So you HAVE to keep these beasts topped off with Oil.
Also someone said "that would be a fun job post warranty" Youre right it would be costly but really having replaced two Turbos in my 1997 911 Turbo, I think this one would be easier given the turbo is on top of the motor. ON the 911 the turbos are below the motor and I had to remove the whole exhaust system to get to it.

But thanks! THIS IS A TOP TIP (as they say on Wheeler Dealer) Pay attention to your OIL and keep it full at ALL times. The first things that are going to suffer is peripheral items away from the motor that need oil, when the oil gets low!

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2011 X5M
2006 X5 4.8is
2009 Porsche 911 PDK