I have the GT-2 front bumper from the same place you posted. It looks great and fits good too, but the front lip that it came with cannot be used in everyday driving. I have 18s on my car and it is not even lowered and I could not go down or up ANY curbs or high inclines with it on. So I had to remove it and use a flexible rubber lip in it's place. It still rubs some times. But if you did not put that lip on at all, the bumper would be fine and there would be no rubbing. So if your car is lowered as you stated, I would NOT put the extra front lip/diffuser on the aftermarket fron bumper. It will sit too low to the ground.