I have an SQ5 has 21" wheels with factory installed plastic wheel well extensions. The Rocker panel is same as Q5 S-Line. I ordered front mud guards using part number you recommended. Does say "not for S-Line or SQ5". I thought if fit your S-Line perhaps will work on my SQ5, rocker panel is the same. The plastic wheel well extensions do not touch rocker panel and the top of the mud guard does not extend up past the rocker there is no problem. Noticed when test fitting guard the bottom piece that extends under rocker and passes along the back of the wheel well needs a small notch cut (won't be seen) at the end for the guard to sit flush with the front and bottom of the rocker. I also noticed that one of the tabs used to screw the guard under rocker (closest to the exterior) does not have any place to allow screw to connect to the bottom of the rocker. That tab could be cut off. How was your guard installed? Did you install it?