Does anyone was venture a guess on what the price difference will be on similarly loaded G8s?

If I decide on a G8 it will be my only car and therefore my daily driver, and a V8 wouldn't be necessary if it raised the cost substantially. However if its only slightly more, I'd probably have to get it.

25k for a base V6, 28k loaded. 30k base V8, 35k loaded V8. This is basically what has been thrown around.