Just a friendly suggestion to be careful when securing down the clear plastic pieces such as head light covers. If you overtighten them the plastic will dimple down around the screws and form raised waves between them. The deformation is not reversable and IMHO really detracts from the hard earned finish of the car. One thing to do is have the car in light such that you get a reflection or glare off of the piece. You will see the reflection bend if the screw is too tight and loosening will allow the piece to go flat again. They should be snugged just to hold the piece in place. This will also prevent future star-cracking around the screws. If you are worried about sealing out water, you might consider using a slightly thicker closed-cell foam tape as a gasket. I don't have part numbers but have seen many types offered by 3M. If your car will only see rain if it's caught by the weather, I would go easy on the plastic rather than worrying about a seal and over tightening the pieces down.