Hi ZForce,
I finally got around to adding the 20mm spacers to the fronts.
It has also been lowered with Tein Springs and the actual drop is [.9 inch] in front, [.8 inch] in the rear. Same tires HandKook, model, VENTUS V12, Fronts 255/35/19, Rears 305/30/19. There is no rubbing with or without the spacers. The reason I added the spacers were for two reasons, a wider stance front & rear but more to increase the distance from the spider of the wheel mag from the front large calipers. One day after I recover from all my savings which has been poured into the Z I would like to find some wheels with nice offsets to get the lip. The wheels I want but can't afford are the "WORK Gnosis GS2" seen in this post.
WORK Gnosis GS2 20x9.5 / 20x11.0 - MSL Silver
I personally do not notice the change with the understeer.
Here are some updated pics.
Eventually down the road maybe a year or two I am considering new wheels Rear (19 x 11) with a tire size of 315 but need to research who is running these and what their experience has been.