I tell you what, I haven't heard anyone mention having more offset at the front wheels, but with my current set up (stock Nismo wheels with Swift springs), I'm almost considering a larger spacer up front, smaller in the rear to even them out. Tried to measure it yesterday without a plumb line, and it looked like @ 13-15MM in front, and 7-10 in the rear to run flush with the fender. I realize this is also dependent on the brand of tire (I'm running stock Yokohamas), but I'm trying hard to only buy one set and be done with it.
It's frustrating because I haven't heard one person on this thread, or others related to spacers, talk about running larger spacers in the front....