X5 35i Turbocharger Longevity?
 

Hey guys, I'm looking at a 2011 X5 35i to replace our E53. The rear air bags and compressor have been replaced. The turbo has been replaced with a rebuilt unit, the car only has 129,000 miles.

What is the typical life span of a single turbo on these N55 cars? I'm surprised to hear the turbo was replaced at a relatively low mileage.