i cant say shit to the headlight/taillight covers! just goes with what im doin to my truck... but as for the other 2 - their FUNCTIONS are the hood guard - to create a flow of air to prevent bugs and SMALL rocks from taggin your windshield... and the window things - so you dont get such a good breeze in the cab, and you can roll your windows down slightly when its raining to get a flow of air... but its with all these lowrider trucks or whatever that start makin em take up half the damn windows, or having rose and jesus stickers all over them :twak