drop zone suspension

dose anyone know how much these springs will lower my car? i've heard 2 inches from one person and 3 inches from another. also i have 17's with 205/40/17 tires, do you think i'll rub if i do drop it 3 inches?

Never heard of them before but you shouldnt have any problems when you drop it except for when you take HARD corners or U-turns for example.