I was wondering if any of you have polished your turbo manifolds for better air flow, and if so what result did you see. I decided to do this while my TO4S was off the car and was able to make the passages MUCH smoother than the original rough cast iron. I was also wondering how this would effect mu tuning. I am tuned very rich at the moment, so I am wondering if it will change much once I put the turbo back on.