H&R Cup Suspension Kit

Hello, I'm new to the forum and I need some advice. I own a 199 328I with 18inch Breyton Inspiration sizes 8.5 in the front and 9.5 in the rear. For tires, I have 225 40 18 in the front and 255 35 18 in the rear. The problem is that I am getting a slight rub on the inside when I hit a deep dip or I Have people in the back seats. I was exploring doing a H&R Cup Suspension kit application but I have concerns about the rub. Someone suggested that I put spacers in the rear to eliminate the inside rub. My fenders are already rolled and I think that the cup kit will tuck the rear wheels a little. CAn anyone give me some advice on whether i should continue with my plans or not. Or please make suggestions on what you have done or what you know. Oh yeah, I live in New York City.......Please help, I want the aggressive look..........