What wheel is that?
Against what others may choose, I went with a 5x114.3 and variable pcd lugs on a centerline Rev7 20x9 et27
Staying with an 18" wheel/tire combo or downsizing to a 17" can save a bunch of unsprung weight. There doesn't seem to be much weight difference between a 18" tire and a 20" tire from what I'm seeing on TireRack, so the wheel is where you would save weight. The nice forged 18" wheels I've looked at come in in the 18 to 21 pound range (18x8 - 18x10). The mid-range forged wheels tend to be 3 or 4 pounds heavier in the same size. And the cheap ones are almost as heavy as cast wheels at close to 30 pounds. The biggest difference in weight always seems to be the spoke design of the wheel; i.e. the more spokes or the more intricate the spoke design the more they weight. Show or go! 😉
I want to go to a 20 (+2) which "can" increase the weight of the wheel depending on the construction of the wheel. Really tough to make a light weight cast wheel. I've seen very few at less than 30 pounds as a 20" wheel. A billet wheel would be great and weigh less, but at 3 to 5 times the cost of forged wheels. And forged wheels seem to be 2 to 4 times the cost of a cast wheel.