Lol^
If you look up unmarked vehicles, they may come up.
I know I hate saying this and I'll explain below-
looks up undercover vehicles...
i hate the term undercover because an undercover vehicle doesn't have lights, siren, or even a radio. They don't even have government plates, but somebody thought of an unmarked car and labeled it undercover and the term rose.
for the presidential stuff, you may have to get someone to get some texturing and maybe a bit of modeling done.