No shop in Ga. will do it less than 32% on a passenger car. Trucks(SUV's), you can do the back windows as dark as you want. You have to read about the tint laws to understand what they apply to. http://home.pcisys.net/~bpc/auto_law/tint/
They can get fined for doing illeagal tint. If you want it illeagal, you have to find somebody that knows how to do it on the side. Then you worry about getting a ticket, which may or may not happen.