You need to have them check the uppipe to the turbo and make sure it is not clogged...I have seen a few at my dealership. We replace the up pipe and if done it time, does no damage to the turbo. Although, I have had to replace a few turbos.
All of this was on 07 Sti's. I was told the problem was from overboosting, which breaks up the stuff in the cat and it clogs the turbo, although I have not had that confirmed.