Peterrat

I have a 2004 Forester XT with 140,000KM. Recently I heard a grinding noise that sounds like metal on metal and it feels like I am loosing performance. The problem seems to come and go. Can someone tell me what turbo failure sounds like and what the symptoms are? Also how bad will this be to fix and do I have any other options? I'm thinking of dumping the car quickly before it goes on me an I'm stuck with what I assume to be a big turbo bill. What dealer scams should I watch for on this?