Pre-installing the chin spoiler is recommended. The unit's instructions call for tucking the spoiler a 1/4-inch back from the front of the front of the bumper, as it is on '03-'04 Mach 1s. However, we like the flush-with-the-bumper look, and set our 'Stang's spoiler up as a true extension of the bumper. Note that self-tapping Tec screws are used for the initial fitment. The holes created by the screws are used as reference points for drilling 1/4-inch holes for the spoiler's actual mounting hardware.