I have an 09xS sedan on Swift springs along with Hochkis sway bars and front and rear camber kits. My car has the front OEM chin spoiler also. I have yet to bottom out the chin spoiler but will admit you should use common sense on some dips and larger pot holes, but I would do that even if my car wasn't lowered and didn't have the chin spoiler. I really like the modest drop that the Swift springs gave me and feel the car is at a height the factory should have given the car.