I'll bet I would reduce the un-sprung weight of the car by 100 lbs with the Bundts.
Zak,
You would loose that bet. I have the 5.5 inch wide aluminum wheels from an 80's MB, the one that is painted black, with white stripes, that looks like a steel wheel and uses the full hub cap.
These are lighter than Bundts, and, if I remember correctly, it is 10 lbs per wheel lighter, or 40 lbs savings total. So, something less than 40 lbs reduction for Bundts for the total car.
But, I can assure you I can feel the difference.
Quicker off the line (less rotational mass), more nimble turn in (less gyroscopic effect), and better on the bumps (less unsprung weight).
I don't know why everyone always focuses on the unsprung weight and doesn't mention the other too.
They are all significant.
Have fun !!!