Be advised that when you change ride heights, you are also changing the alignment, roll centers, handling characteristics and aerodynamic behavior of your car. I would definitely not suggest lowering your car 1/2" in the front and 1" in the rear. This will completely eliminate the factory "rake" of 1/2" from front to rear.
Further, unless you are getting the exact same spring rates that came on the car, you will be changing the relative roll stiffness on each end of the car, which will further change the handling characteristics.
If your goal is to simply lower the car for appearance purposes, consider all the other things you are changing before doing so.
If your goal is to improve handling, lowering the car will help, but I would recommend getting adjustable shocks with adjustable spring perches so that you can independently adjust the ride height on each corner, properly corner weight your car, then do a 4-wheel realignment. The adjustable shocks will help you fine-tune the handling after you've made all these changes.