MOREDLEG,I kinda got caught up in the "dealer diagnosis" you can do some "homework" before buying a turbo. Pull the air intake tube off at filter box and at the turbo. You should be able to reach turbo impeller, if so check for any side to side movement, then back and forth movement and of course give it a spin with your fingers. If you hear any grinding noises while spin by hand then you have a problem. Then there is the obvious...have you or the "daff" wrench pullers at the dealer checked
your turbo hoses, clamps, intake manifold and intercooler for leaks?
slightest leak in any of these will cause you issues.