[dumdum]

Like mentioned earlier in this post,it could be a pre turbo exhaust leak.An easy way to find an exhaust leak is to have a buddy get a couple of rags and start the car.Let the car idle and have your buddy cover the exhaust tip with his hand (and rags) for 15 seconds at a time.Don't just sit there with the exhaust plugged for like a minute or something.You listen for the leaks up front.Next step would be to pull the turbo inlet pipe and look into the compressor housing inlet.Look for visable damage on the outside of the wheel and for grooving on the compressor housing inlet where the wheel could have contacted.Rub your finger around the compressor wheel and see if you find metal shavings.