Upon taking Top Fuel's advice, I read an article on Tire Rack about wheel weight.
Wheel Tech: Road Wheel Weights Can Affect Your Vehicle's Show...& Go!
They tested three different sets of wheels on some BMW 3 series cars, each fitted with different tires. While the wheel weights didn't vary as dramatically as the Hot Rod magazine article, they also used three different cars instead of using the same car. The differences in fuel consumption were there, but I suspect could also be influenced by other factors. In the Tire Rack example, the stock configuration had the lowest fuel consumption. The 'lightweight' combination used more fuel.
Originally Posted by Tire Rack Wheel Tech: Road Wheel Weights Can Affect Your Vehicle's Show...& Go!