I get boost and vac but is leaking oil. Only smokes on cold start and if I step on the pedal hard. Car has 60 on the clock. Clean and was not abused. Everything is stock. Head gasket was changed and a complete tune up done. Any ideas on what it can be, or, is the turbo cooked ? In that case, where can I find a replacement, or, something similar that would be an exact fit ?