Isn't the only way to optimise the Contour/mondeo TB is by increasing the diameter of the butterfly, thus increasing the flow of air, polishing might be detrimental to airflow, slightly pitted surfaces have better flow dynamics than smoothed/mirror finished surfaces.
Knife edging might also make a small difference, maybe, but the volume of air your engine is getting is the same.
How about using a Focus header, with the focus central 65mm TB, and the throttle cable to match?
