I've been through 18 pages of search results looking for a thread were I quoted a magazine article to that effect. Unsuccessfully.
As I recall they replaced steel rims with plus sized Centerline forged alloys and showed a weight savings (looking at the fronts of a car with massive rear tires)
Just so I haven't totally wasted that time:
http://ecomodder.com/forum/showthrea...orth-5904.html 2008, 11p.
http://ecomodder.com/forum/showthrea...-mpg-5441.html 2008, 2p.
http://ecomodder.com/forum/showthrea...-mpg-4508.html 2008, 7p.
http://ecomodder.com/forum/showthrea...loys-2681.html 2008, 4p.
http://ecomodder.com/forum/showthrea...els-28551.html 2014, 2p.
Lots of interest in 2008.
I believe early Porsche Fuchs alloys came with a 4.5" width, but they are rare.