When I got my Z for $500, the Turbo was coked up and seized. Find a reputable local diesel shop and bring in the turbo, and they will rebuild it for you, or if you are cheap like me, spend $100 on rebuild parts and rebuild it yourself! A turbocharger only has about 15 parts to it, and as long as you scribe accurately how they came apart, they go back together the same way. I even swapped in a 300Z centre section so now I have coolant and oil in my turbo! If you can rebuild a carb, you can rebuild a turbo.