I have alignment tools, so when I lowered my Z06, I checked before and after each step. On my car, the rear could be lowered 1" and it stayed within specs, although with slightly more negative camber. Lowering the front 1" adds about 0.7 to 0.8 degree of negative camber, which was too much. In fact, it started off uneven left to right (but still within spec). I had to remove the upper control arm from the frame to be able to get out the adjusting bolt, so I added appropriate sized washers between the frame and A-arm until the camber came back to about 0.6 ro 0.7 degree negative both sides. When you take out negative camber at the top, the toe-in becomes much higher, so I then had to adjust that too.
When you adjust camber by adding shims at the top or adjusting the eccentrics at the bottom, be sure you change the front and rear ends of the A-arm the *same* amount, or you will change the caster.
The bottom line is that you will need to have the alignment adjusted, no way to avoid it. This is also a good time to tidy up a sloppy factory alignment. I would not drive the car long without doing this, because the tires are very expensive, and bad alignment causes greatly increased tire ware.