I have H&R springs which drop around 20mm. Ride quality only slightly firmer than standard. I'm running 8x18 Omanyt wheels with 225 40 18 - No rubbing and no gap between arches and tyres. tried Passat Macau 7.5 x 17 with 235 tyres and they rubbed so as suggested before I would recommend changing tyres to 225 or 215 depending on drop.