That's great Rich, I'm glad you've got that solved now!

And yes, you should definitely notice a major improvement in render quality in shading and reflections.

Getting the vertex normals to come through makes a huge difference because they come from the original NURBS model, so when they're used to shade the polygons it makes them have the same shading appearance as the original NURBS surface. If they don't come through then the shading normals are cooked up by averaging the normals of the polygon faces together that share a point in common, but that's not as good as using the original information directly.

- Michael