Well, the front brakes I got from ebay have the wrong brackets ( they sent me the base model brackets instead of the z51)

so I am put in a position to make a choice here. These z51 rotors minimum wheel diameter is 18" however the brackets I have is for the base rotors which min. wheel diameter is 17" So I could buy the right brackets and run 18's or I could by the smaller rotors that match my brackets and run 17's
I am planning on having the car sit low and I think I could pull of 18's with no problem but I am really having a hard time making a decision.