Rays Eco Wheels

So I've read a lot about swapping the wheels on the Leaf out for lighter versions to increase efficiency in city driving. I couldn't find any hard numbers or studies to back this up, but it only seems logical that lighter=better. Anyway, found these wheels that seem to cater to fuel economy, has anyone seen these wheels, or does anyone have them on their Leaf? Does anyone have any hard data to support that lighter wheels would be better (same size & tires, all other things equal of course) ?

P.S. I think the blue wheels would look awesome on Glacier Pearl, just sayin.

http://www.rays-msc.com/wheels/index.cgi?b=2

Rays is very nice! It looks like this selection is light and running the larger diameters with narrower widths. If $700-$900 per wheel is fine, mount em up. I would love to see the pics.

This looks hot. Similar to the Rota j-mag.