Vehicle modifications can take many forms, from simple modifications such as light window tinting to under-vehicle LED lighting to the more complex frame and suspension modifications.
While window tinting might not be as big of deal on side windows, laws vary by state on the degree of tint you can use on your front windshield.
To paraphrase the Almond Joy commercial, sometimes you feel like a tint, sometimes you don't. In states like California, having any tint on your front windows is verboten. It's only casually enforced, but it's still illegal. In that case, something like this setup might come in handy: a Russian gent on installed two power windows in one door, and tinted one of them.