Optical quality of the 28-85 f/3.5-4.5D vs 24-85 kit lens

I am saving the money to purchase the D600. I already own the above mentioned D series lens and was curious about the image quality fifferences between these two lenses. I am aware of the mechanical differences between a G lens and the olxer D. I am also aware of the focal range differences. What I would be most concerned with is wide open performance.
Anyone care to speculate?
--

In god we trust, all others are suspects

http://www.md-lightsource.com

Licensed firearms dealer in Houston, Texas