I had mine lowered almost an inch with the stock bolts. We didn't want to go any lower since it was hard to get it on the lifts and ramps at that height. The vette tech that I always had service my car did the work. He also aligned the car after lowering it. I did not experience any noticeable wear patterns after this procedure.
I know with my previous car, when I lowered it 1.5", I had to get camber adjusters to bring back the camber to specs or the tires would wear on the inside.
At what point do I need to worry about that when lowering the Z06? Thanks